Pre-Algebra

419 soru

Soru 301Soru

A community center hosted 5 different skill workshops on a Saturday. The table below shows the number of participants in each workshop and the mean satisfaction rating (on a scale from 1 to 10) reported by the participants in that workshop.

WorkshopNumber of ParticipantsMean Satisfaction Rating
Pottery Basics128.0
Creative Writing89.0
Photography157.0
Graphic Design108.5
Woodworking510.0

What is the overall weighted mean satisfaction rating for all 5050 participants combined across all five workshops?

Cevabı ve açıklamayı göster

Cevap: 8.168.16

Cevap

The overall weighted mean satisfaction rating for all 50 participants is 8.16.
The correct answer is obtained by calculating the weighted mean. Multiplying each workshop's rating by its number of participants gives the total points contributed by that group. Adding these products gives a total of 408 satisfaction points across all 50 participants. Dividing 408 by 50 yields an overall weighted average of 8.16.

Adım Adım Çözüm

1
Calculate the total sum of satisfaction ratings for each workshop
Pottery: 12×8.0=9612 \times 8.0 = 96; Creative Writing: 8×9.0=728 \times 9.0 = 72; Photography: 15×7.0=10515 \times 7.0 = 105; Graphic Design: 10×8.5=8510 \times 8.5 = 85; Woodworking: 5×10.0=505 \times 10.0 = 50
Each participant's rating contributes to the total sum for their workshop.
2
Sum the total satisfaction points across all workshops
96+72+105+85+50=40896 + 72 + 105 + 85 + 50 = 408
This gives the total combined satisfaction points for all participants.
3
Divide the total combined satisfaction points by the total number of participants
40850=8.16\frac{408}{50} = 8.16
The weighted mean requires dividing the overall sum of scores by the total sample size (5050 participants).

Anahtar Kavram

Weighted Mean from Summary Data Tables
Soru 302Soru

A fair game spinner is divided into 88 equal sectors numbered 11 through 88. If Maya spins the spinner once, what is the probability that the spinner lands on a number strictly greater than 55?

Cevabı ve açıklamayı göster

Cevap: 38\frac{3}{8}

Cevap

The probability that the spinner lands on a number strictly greater than 5 is 38\frac{3}{8}.
The sample space consists of 8 equally likely outcomes: {1, 2, 3, 4, 5, 6, 7, 8}. The event 'landing on a number strictly greater than 5' consists of 3 outcomes: {6, 7, 8}. The probability is the ratio of favorable outcomes to total outcomes, which gives 3/8.

Adım Adım Çözüm

1
Determine the total number of possible outcomes in the sample space.
The total number of equal sectors is 88, so total outcomes = 88.
The spinner is divided into 8 equal sections numbered 1 through 8.
2
Identify the favorable outcomes that satisfy the condition 'strictly greater than 5'.
The numbers strictly greater than 55 are 66, 77, and 88. Thus, there are 33 favorable outcomes.
Strictly greater than 5 excludes 5 itself.
3
Calculate the probability using the basic probability formula.
P(greater than 5)=Number of favorable outcomesTotal number of outcomes=38P(\text{greater than } 5) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{3}{8}.
Theoretical probability is the ratio of favorable outcomes to total sample space outcomes.

Anahtar Kavram

Basic Probability of Simple Events
Tahmini Süre:45s
Soru 303Soru

A freight shipping company calculates the total fuel consumption, CC in gallons, for a cargo vessel using the equation C=45hC = 45h, where hh represents the number of hours the vessel operates at cruising speed. If the vessel consumed a total of 3,1503,150 gallons of fuel on a recent journey, for how many hours did the vessel operate at cruising speed?

Cevabı ve açıklamayı göster

Cevap: 7070

Cevap

70 hours
To find the number of hours hh, substitute 3,1503,150 for CC in the equation C=45hC = 45h, yielding 3,150=45h3,150 = 45h. Dividing both sides by 4545 gives h=70h = 70. Therefore, the vessel operated at cruising speed for 7070 hours.

Adım Adım Çözüm

1
Identify the given values and formula from the problem statement.
Formula: C=45hC = 45h, with total fuel consumption C=3,150C = 3,150 gallons.
This sets up the linear one-step equation to solve for the unknown operating time hh.
2
Substitute C=3,150C = 3,150 into the equation.
3,150=45h3,150 = 45h
Replacing the variable CC with its given numeric value leaves a one-step multiplication equation in terms of hh.
3
Isolate hh by performing the inverse operation.
h=3,15045=70h = \frac{3,150}{45} = 70
Dividing both sides of the equation by 4545 isolates hh to find the number of hours.

Anahtar Kavram

Solving One-Step Multiplication Equations
Tahmini Süre:1m 0s
Soru 304Soru

A high school robotics team recorded their scores across 5 qualification matches: 90,78,86,82,90, 78, 86, 82, and 8484. In their 6th qualification match, the team earned a score of xx, which increased their overall 6-match mean score by 33 points compared to their 5-match mean score. What is the positive difference between the median and the mean of all 6 match scores?

Cevabı ve açıklamayı göster

Cevap: 22

Cevap

The positive difference between the mean and median of all 6 match scores is 2.
The mean of the original 5 matches is (90+78+86+82+84)÷5=84(90 + 78 + 86 + 82 + 84) \div 5 = 84. Since the 6th match increases the overall mean by 3, the new mean for 6 matches is 84+3=8784 + 3 = 87. The total score for all 6 matches is 87×6=52287 \times 6 = 522. Subtracting the original total of 420 gives the 6th match score: 522420=102522 - 420 = 102. Arranging all 6 scores in ascending order gives 78,82,84,86,90,10278, 82, 84, 86, 90, 102. The median is the average of the middle two numbers, 84 and 86, which equals 85. The positive difference between the mean (87) and the median (85) is 8785=287 - 85 = 2.

Adım Adım Çözüm

1
Calculate the mean of the first 5 matches.
Sum = 90+78+86+82+84=42090 + 78 + 86 + 82 + 84 = 420. Mean = 420÷5=84420 \div 5 = 84.
The initial mean is needed to establish the target mean for 6 matches.
2
Determine the new 6-match mean and calculate the 6th score xx.
New Mean = 84+3=8784 + 3 = 87. Total required sum = 87×6=52287 \times 6 = 522. x=522420=102x = 522 - 420 = 102.
An increase of 3 in the mean score means the new average across all 6 matches is 87.
3
Order all 6 match scores from least to greatest and find the median.
Sorted scores: 78,82,84,86,90,10278, 82, 84, 86, 90, 102. Median = (84+86)÷2=85(84 + 86) \div 2 = 85.
For an even number of values, the median is the average of the two central numbers after sorting.
4
Calculate the positive difference between the 6-match mean and median.
8785=2|87 - 85| = 2.
Subtracting the median (85) from the mean (87) yields the required difference.

Anahtar Kavram

Descriptive Statistics: Finding Missing Data Points, Mean, and Median
Soru 305Soru

A juice bar allows customers to create a custom smoothie by selecting exactly 11 fruit base out of 44 available options and 11 liquid base out of 33 available options. How many different custom smoothie combinations of 11 fruit base and 11 liquid base are possible?

Cevabı ve açıklamayı göster

Cevap: 12

Cevap

The total number of possible smoothie combinations is 12.
According to the Fundamental Counting Principle, if there are mm ways to make a first choice and nn ways to make a second choice, there are m×nm \times n total possible pairs. Here, multiplying 44 fruit choices by 33 liquid choices yields 4×3=124 \times 3 = 12 total smoothie combinations.

Adım Adım Çözüm

1
Determine the number of options for each independent choice
Fruit base options = 4; Liquid base options = 3
Each choice is independent of the other.
2
Multiply the number of options for each choice using the Fundamental Counting Principle
4 x 3 = 12
To find the total number of combinations across multiple independent categories, multiply the number of choices in each category together.

Anahtar Kavram

Fundamental Counting Principle
Tahmini Süre:45s
Soru 306Soru

An artisan pottery workshop uses a total of cc kilograms of clay to make ceramic vases. If each vase requires 44 kilograms of clay and the workshop produced 1818 vases in total, which of the following equations models this scenario, and what is the total amount of clay cc used?

Cevabı ve açıklamayı göster

Cevap: c4=18\frac{c}{4} = 18; c=72c = 72

Cevap

The correct equation is c4=18\frac{c}{4} = 18, which gives c=72c = 72 kilograms.
The total amount of clay cc divided by the 44 kilograms required per vase gives the total number of vases, 1818. Thus, c4=18\frac{c}{4} = 18. Multiplying both sides by 44 yields c=72c = 72 kilograms.

Adım Adım Çözüm

1
Define the algebraic relationship from the scenario.
The total amount of clay cc divided by the clay required per vase (44 kg) equals the total number of vases (1818). This gives the equation c4=18\frac{c}{4} = 18.
Dividing the whole quantity into equal parts of size 44 determines the count of items.
2
Solve the one-step equation for the total clay cc.
c=18×4=72c = 18 \times 4 = 72.
Multiply both sides of the equation by 44 to isolate the variable cc.

Anahtar Kavram

Formulating and solving one-step linear equations from word problems involving rates.
Tahmini Süre:1m 0s
Soru 307Soru

A commercial printing press uses large rolls of paper for magazine production. During a morning shift, a technician uses 49\frac{4}{9} of the total mass, mm (in kilograms), of a full paper roll. If the mass of paper used during the shift is 3636 kilograms, what is the total mass mm, in kilograms, of the full paper roll?

Cevabı ve açıklamayı göster

Cevap: 81

Cevap

The total mass of the full paper roll is 81 kilograms.
To find the total mass mm, set up the equation 49m=36\frac{4}{9}m = 36. Multiplying both sides by the reciprocal 94\frac{9}{4} yields m=36×94=81m = 36 \times \frac{9}{4} = 81 kilograms.

Adım Adım Çözüm

1
Set up the one-step algebraic equation based on the given word problem.
49m=36\frac{4}{9}m = 36
The problem states that 49\frac{4}{9} of the total mass mm equals 3636 kilograms.
2
Isolate the variable mm by multiplying both sides of the equation by the reciprocal of 49\frac{4}{9}, which is 94\frac{9}{4}.
m=36×94m = 36 \times \frac{9}{4}
Multiplying by the reciprocal cancels out the fraction coefficient on the left side.
3
Simplify the numerical calculation.
m=9×9=81m = 9 \times 9 = 81
Dividing 36 by 4 gives 9, and multiplying 9 by 9 results in 81.

Anahtar Kavram

Solving One-Step Linear Equations involving Fractional Coefficients
Soru 308Soru

Four real estate agents reported the proportion of their home listings that sold above asking price last month as follows: Agent W reported 3150\frac{31}{50}, Agent X reported 58\frac{5}{8}, Agent Y reported 63%63\%, and Agent Z reported 0.640.64. Place the four agents in order from the smallest proportion of listings sold above asking price to the largest proportion.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order from smallest to largest proportion is Agent W (31/50 = 0.62), Agent X (5/8 = 0.625), Agent Y (63% = 0.63), and Agent Z (0.64).
To place the values in ascending order, convert all values to decimals: Agent W = 31/50 = 0.620, Agent X = 5/8 = 0.625, Agent Y = 63% = 0.630, and Agent Z = 0.640. Arranging these from least to greatest gives 0.620 < 0.625 < 0.630 < 0.640, corresponding to the sequence Agent W, Agent X, Agent Y, and Agent Z.

Adım Adım Çözüm

1
Convert each fraction, percentage, and decimal to a common decimal representation to facilitate comparison.
All four numbers will be expressed as decimals rounded/extended to three decimal places.
Converting all values to decimals makes comparing their magnitudes straightforward.
2
Convert Agent W's value: 3150\frac{31}{50}.
3150=62100=0.620\frac{31}{50} = \frac{62}{100} = 0.620
Multiply numerator and denominator by 2 to convert to hundreds.
3
Convert Agent X's value: 58\frac{5}{8}.
58=5÷8=0.625\frac{5}{8} = 5 \div 8 = 0.625
Perform long division of 5 by 8.
4
Convert Agent Y's value: 63%63\%.
63%=63100=0.63063\% = \frac{63}{100} = 0.630
Divide percentage value by 100 to obtain decimal format.
5
Note Agent Z's value, which is already a decimal.
0.64=0.6400.64 = 0.640
Align decimal places with the other converted values.
6
Order the decimal values from smallest to largest.
0.620<0.625<0.630<0.6400.620 < 0.625 < 0.630 < 0.640, which corresponds to Agent W, Agent X, Agent Y, and Agent Z.
Comparing digits from left to right establishes the proper sequence.

Anahtar Kavram

Comparing and ordering real numbers by converting fractions, decimals, and percentages into a unified numerical format.
Tahmini Süre:1m 15s
Soru 309Soru

A custom bicycle workshop builds specialized cargo bikes. The total frame assembly weight, WW pounds, is determined by adding a fixed base frame weight of ff pounds to the weight of nn reinforced structural struts, where each strut weighs 2.4 pounds. For a cargo bike configured with 5 structural struts, the total frame assembly weight is 26.0 pounds. Which of the following one-step linear equations can be solved to find ff, the weight in pounds of the fixed base frame?

Cevabı ve açıklamayı göster

Cevap: f+12.0=26.0f + 12.0 = 26.0

Cevap

The equation f+12.0=26.0f + 12.0 = 26.0 correctly models the scenario and can be solved to find the base frame weight ff.
The total frame assembly weight is the sum of the fixed base frame weight ff and the total weight of the struts. Since there are 5 struts weighing 2.4 pounds each, their combined weight is 5×2.4=12.05 \times 2.4 = 12.0 pounds. Adding this to the base frame weight ff gives the total weight of 26.0 pounds, represented by the equation f+12.0=26.0f + 12.0 = 26.0.

Adım Adım Çözüm

1
Calculate the total weight contributed by the structural struts.
Weight of struts = 5×2.4=12.05 \times 2.4 = 12.0 pounds.
Each of the 5 struts weighs 2.4 pounds, so multiplication gives their total combined weight.
2
Set up the linear relationship for total frame assembly weight.
Total weight = Base frame weight + Struts weight, which gives f+12.0=26.0f + 12.0 = 26.0.
The total assembly weight (26.0 pounds) is the sum of the fixed base frame weight (ff) and the struts weight (12.0 pounds).

Anahtar Kavram

Translating verbal context into a one-step linear equation
Tahmini Süre:1m 30s
Soru 310Soru

An automated manufacturing line produces component X and component Y in a ratio of 4:74:7. During a single production run, a total of 1,7601,760 components were produced. How many more component Y than component X were produced during this run?

Cevabı ve açıklamayı göster

Cevap: 480

Cevap

480 more component Y than component X were produced.
The total ratio parts equal 4+7=114 + 7 = 11. Dividing the total production of 1,7601,760 components by 1111 yields 160160 components per ratio part. Since component Y has 77 parts and component X has 44 parts, component Y has 74=37 - 4 = 3 more parts than component X. Multiplying 3×1603 \times 160 gives 480480, which is the exact additional amount of component Y produced.

Adım Adım Çözüm

1
Find the total number of ratio parts
4+7=114 + 7 = 11 total parts
The ratio 4:74:7 indicates that for every 4 units of component X, there are 7 units of component Y, making up 11 equal parts of the total production.
2
Calculate the value of one ratio part
1,76011=160\frac{1,760}{11} = 160 components per part
Divide the total number of components produced by the total number of ratio parts.
3
Determine the difference in ratio parts between component Y and component X
74=37 - 4 = 3 parts
Subtract the ratio units of component X from component Y to find the difference in ratio parts.
4
Calculate the difference in actual components produced
3×160=4803 \times 160 = 480 components
Multiply the difference in ratio parts by the value of a single ratio part.

Anahtar Kavram

Solving Part-to-Part and Part-to-Whole Ratio Word Problems
Tahmini Süre:1m 0s
Soru 311Soru

A community garden allocates its total area among three crops: vegetables, herbs, and flowers. Exactly 38\frac{3}{8} of the total area is dedicated to vegetables, and 40%40\% of the remaining area is planted with herbs. If the remaining flower section covers 270270 square feet, what is the total area, in square feet, of the community garden?

Cevabı ve açıklamayı göster

Cevap: 720720

Cevap

The total area of the community garden is 720720 square feet.
The correct answer is 720720 square feet. Vegetables take 38\frac{3}{8} of the total area, leaving 58\frac{5}{8}. Herbs take 40%40\% of 58\frac{5}{8}, which equals 25×58=28\frac{2}{5} \times \frac{5}{8} = \frac{2}{8} of the total. Subtracting the herb portion from the remaining portion leaves 5828=38\frac{5}{8} - \frac{2}{8} = \frac{3}{8} of the total for flowers. Solving 38T=270\frac{3}{8} T = 270 gives T=720T = 720 square feet.

Adım Adım Çözüm

1
Calculate the remaining fractional area after allocating space for vegetables.
Since vegetables occupy 38\frac{3}{8} of the garden, 138=581 - \frac{3}{8} = \frac{5}{8} of the total area remains.
The total area represents 11 whole, so subtracting the vegetable fraction gives the remaining fraction.
2
Determine the fractional area allocated to herbs.
Herbs take 40%40\% of the remaining 58\frac{5}{8}. Converting 40%40\% to a fraction gives 25\frac{2}{5}. Calculating 25×58=28=14\frac{2}{5} \times \frac{5}{8} = \frac{2}{8} = \frac{1}{4} of the total garden area.
Multiplying the percentage by the remaining fraction yields the portion of the whole garden used for herbs.
3
Find the fractional area remaining for flowers.
Subtract the herb fraction from the remaining area after vegetables: 5828=38\frac{5}{8} - \frac{2}{8} = \frac{3}{8} of the total area.
The flower section represents whatever area is left after both vegetables and herbs are accounted for.
4
Set up an equation to solve for the total garden area TT.
38T=270    T=270×83=720\frac{3}{8} T = 270 \implies T = 270 \times \frac{8}{3} = 720 square feet.
Dividing the actual area of flowers by its fractional share gives the total garden area.

Anahtar Kavram

Multi-step word problems involving sequential fractions and percentages of a remaining amount.
Tahmini Süre:1m 15s
Soru 312Soru

A bookstore recorded the number of books purchased by a sample of 2525 customers. The frequency table below summarizes the purchases made by 2020 of these customers:

Number of Books PurchasedFrequency
16
25
34
43
52

The remaining 55 customers each purchased the exact same number of books, nn. If the mean number of books purchased by all 2525 customers is 2.82.8, what is the median number of books purchased by the entire group of 2525 customers?

Cevabı ve açıklamayı göster

Cevap: 3

Cevap

The median number of books purchased by the entire group of 25 customers is 3.
The total number of books purchased by all 25 customers is 25×2.8=7025 \times 2.8 = 70. The sum of books for the first 20 customers is (1×6)+(2×5)+(3×4)+(4×3)+(5×2)=50(1 \times 6) + (2 \times 5) + (3 \times 4) + (4 \times 3) + (5 \times 2) = 50. The remaining 5 customers bought a total of 7050=2070 - 50 = 20 books, meaning each bought 20÷5=420 \div 5 = 4 books (n=4n = 4). Updating the frequency table, the number of customers buying 4 books becomes 3+5=83 + 5 = 8. For 25 ordered values, the median is the 13th value. Calculating cumulative frequencies: 6 customers bought 1 book, 11 bought 2\le 2 books, and 15 bought 3\le 3 books. Therefore, the 13th value is 3.

Adım Adım Çözüm

1
Calculate the total number of books purchased by all 25 customers.
Total Books=25×2.8=70\text{Total Books} = 25 \times 2.8 = 70
Mean is equal to total sum divided by total count, so total sum equals mean multiplied by count.
2
Calculate the sum of books purchased by the first 20 customers listed in the table.
(1×6)+(2×5)+(3×4)+(4×3)+(5×2)=6+10+12+12+10=50(1 \times 6) + (2 \times 5) + (3 \times 4) + (4 \times 3) + (5 \times 2) = 6 + 10 + 12 + 12 + 10 = 50
Multiply each book amount by its corresponding frequency and sum the results.
3
Determine the value of nn for the remaining 5 customers.
Remaining Books=7050=20\text{Remaining Books} = 70 - 50 = 20, so 5n=20    n=45n = 20 \implies n = 4
Subtracting the sum of the 20 customers from the grand total leaves the books purchased by the 5 remaining identical customers.
4
Update the frequency distribution and locate the median position.
New frequencies: 1 book (6), 2 books (5), 3 books (4), 4 books (3 + 5 = 8), 5 books (2). The median of 25 values is the 25+12=13th\frac{25 + 1}{2} = 13^{\text{th}} ordered value.
For an odd number of data points NN, the median position is N+12\frac{N+1}{2}.
5
Find the 13th value using cumulative frequencies.
1 book: 6 customers (positions 1-6)
2 books: 5 customers (positions 7-11)
3 books: 4 customers (positions 12-15)
Since position 13 falls within the 3-book group, the median is 3.
The cumulative total reaches 11 at 2 books and 15 at 3 books, so the 13th customer is in the 3-book category.

Anahtar Kavram

Descriptive Statistics: Finding Missing Values via Mean and Computing Median from Frequency Tables
Tahmini Süre:2m 0s
Soru 313Soru

A university professor teaches two sections of Introductory Statistics. Section 1 contains 3030 students and had a mean score of 8282 on the midterm exam. Section 2 contains 2020 students and had a mean score of 9292 on the same exam. What is the overall mean midterm exam score for all 5050 students combined?

Cevabı ve açıklamayı göster

Cevap: 86

Cevap

The overall mean score for all 50 students combined is 86.
To find the combined mean score for all students, calculate the total points earned by multiplying each section's mean by its number of students, summing those products, and dividing by the total number of students: (30×82)+(20×92)30+20=2,460+1,84050=4,30050=86\frac{(30 \times 82) + (20 \times 92)}{30 + 20} = \frac{2,460 + 1,840}{50} = \frac{4,300}{50} = 86.

Adım Adım Çözüm

1
Calculate total points scored by Section 1
30×82=2,46030 \times 82 = 2,460 points
Multiplying the number of students by their mean score yields the sum of their scores.
2
Calculate total points scored by Section 2
20×92=1,84020 \times 92 = 1,840 points
Multiplying the number of students in Section 2 by their mean score yields their point total.
3
Calculate total points scored across both sections
2,460+1,840=4,3002,460 + 1,840 = 4,300 points
Adding the total points from both sections gives the total combined points.
4
Divide total combined points by total combined students
4,30050=86\frac{4,300}{50} = 86
Dividing the sum of all scores by the total number of students gives the combined mean.

Anahtar Kavram

Weighted Mean of Combined Sets
Tahmini Süre:1m 30s
Soru 314Soru

A software engineering team recorded the number of technical bugs resolved daily over a period of 2020 days. The results are summarized in the frequency table below:

Bugs ResolvedNumber of Days (Frequency)
1144
2266
3355
4433
5522

What is the positive difference between the mean and the median number of bugs resolved daily during this 2020-day period?

Cevabı ve açıklamayı göster

Cevap: 0.150.15

Cevap

The positive difference between the mean and median number of bugs resolved daily is 0.150.15.
To find the mean, multiply each bug count by its frequency, sum the products (5353), and divide by the total frequency (2020), yielding a mean of 2.652.65. To find the median for 2020 data points, locate the average of the 10th10\text{th} and 11th11\text{th} values in the cumulative frequency distribution. The 10th10\text{th} value is 22 and the 11th11\text{th} value is 33, making the median (2+3)/2=2.5(2+3)/2 = 2.5. The positive difference between the mean and median is 2.652.5=0.152.65 - 2.5 = 0.15.

Adım Adım Çözüm

1
Calculate the total number of bugs resolved across all 20 days (the sum of products of values and frequencies).
Total Bugs=(1×4)+(2×6)+(3×5)+(4×3)+(5×2)=4+12+15+12+10=53\text{Total Bugs} = (1 \times 4) + (2 \times 6) + (3 \times 5) + (4 \times 3) + (5 \times 2) = 4 + 12 + 15 + 12 + 10 = 53
To find the mean of a frequency distribution, multiply each data value by its frequency and sum the results.
2
Calculate the mean number of bugs resolved per day.
Mean=5320=2.65\text{Mean} = \frac{53}{20} = 2.65
Divide the total sum of bugs resolved by the total number of days (2020).
3
Find the median of the ordered dataset of 20 values.
Median=2+32=2.5\text{Median} = \frac{2 + 3}{2} = 2.5
For n=20n = 20 data points, the median is the average of the 10th10\text{th} and 11th11\text{th} values in order. Looking at cumulative frequencies: 44 values are 11, the next 66 values (positions 55 through 1010) are 22, and the next 55 values (positions 1111 through 1515) are 33. The 10th10\text{th} value is 22 and the 11th11\text{th} value is 33.
4
Compute the positive difference between the mean and the median.
Difference=2.652.50=0.15\text{Difference} = |2.65 - 2.50| = 0.15
Subtract the median (2.502.50) from the mean (2.652.65).

Anahtar Kavram

Descriptive Statistics and Data Representations
Tahmini Süre:1m 15s
Soru 315Soru

A technology company evaluated the annual performance scores of its employees across three departments: Marketing, Engineering, and Customer Support.

- The Marketing department has 2020 employees, with a mean performance score of 9292.
- The Engineering department has twice as many employees as the Marketing department, with a mean performance score of 8686.
- The Customer Support department has 1010 more employees than the Marketing department.
- The overall mean performance score across all employees in all three departments combined is 8484.

What is the mean performance score for the Customer Support department?

Cevabı ve açıklamayı göster

Cevap: 7676

Cevap

The mean performance score for the Customer Support department is 76.
To find the mean score for Customer Support, calculate the total points across all departments (90×84=7,56090 \times 84 = 7,560) and subtract the known total points from Marketing (20×92=1,84020 \times 92 = 1,840) and Engineering (40×86=3,44040 \times 86 = 3,440). The remaining 2,2802,280 points are divided by the 3030 Customer Support employees, yielding a mean of 7676.

Adım Adım Çözüm

1
Determine the number of employees in each department and the total employee count.
Marketing has 2020 employees. Engineering has 2×20=402 \times 20 = 40 employees. Customer Support has 20+10=3020 + 10 = 30 employees. Total employees = 20+40+30=9020 + 40 + 30 = 90.
Accurate employee counts per group are required to calculate weighted sums.
2
Calculate the total combined performance score for all 90 employees.
Total Score=90×84=7,560\text{Total Score} = 90 \times 84 = 7,560.
The sum of all individual scores is equal to the overall mean multiplied by the total number of employees.
3
Calculate the total performance scores for Marketing and Engineering.
Marketing total = 20×92=1,84020 \times 92 = 1,840. Engineering total = 40×86=3,44040 \times 86 = 3,440. Combined Marketing + Engineering total = 1,840+3,440=5,2801,840 + 3,440 = 5,280.
Each department's score contribution is its employee count multiplied by its mean score.
4
Subtract the Marketing and Engineering scores from the total combined score to find the Customer Support total score.
Customer Support total score = 7,5605,280=2,2807,560 - 5,280 = 2,280.
The remaining score points belong to the Customer Support department.
5
Divide the Customer Support total score by the number of Customer Support employees.
Customer Support mean score = 2,28030=76\frac{2,280}{30} = 76.
The mean is the total department score divided by its employee count.

Anahtar Kavram

Weighted Mean and Subgroup Summaries
Soru 316Soru

An artisanal bakery prepares a specialty flour blend consisting of rye, oat, and wheat flour. By weight, 310\frac{3}{10} of the blend is rye flour and 0.450.45 of the blend is oat flour. The remaining portion of the blend is wheat flour. If a single batch of the blend contains 4.54.5 pounds of wheat flour, what is the total weight, in pounds, of the flour blend prepared for the batch?

Cevabı ve açıklamayı göster

Cevap: 18

Cevap

The total weight of the flour blend prepared for the batch is 18 pounds.
To find the total weight of the mixture, first determine the decimal fraction representing wheat flour. Converting 310\frac{3}{10} to 0.300.30, the combined proportion of rye and oat flour is 0.30+0.45=0.750.30 + 0.45 = 0.75. Wheat flour makes up the remaining 10.75=0.251 - 0.75 = 0.25 (25%25\%) of the mixture. Setting up the equation 0.25×Total Weight=4.50.25 \times \text{Total Weight} = 4.5 gives Total Weight=4.50.25=18\text{Total Weight} = \frac{4.5}{0.25} = 18 pounds.

Adım Adım Çözüm

1
Convert the fraction of rye flour to a decimal and sum it with the oat flour portion.
Rye portion = 310=0.30\frac{3}{10} = 0.30; Combined Rye and Oat portion = 0.30+0.45=0.750.30 + 0.45 = 0.75.
Converting all given values to a consistent decimal format allows for straightforward addition.
2
Calculate the remaining portion representing wheat flour.
Wheat portion = 10.75=0.251 - 0.75 = 0.25.
The sum of all proportional components in a whole mixture equals 1.
3
Divide the weight of the wheat flour by its decimal proportion to solve for the total batch weight.
Total weight = 4.50.25=18\frac{4.5}{0.25} = 18 pounds.
Since 25%25\% (0.250.25) of the total weight is 4.54.5 pounds, dividing the part by its decimal rate yields the total whole.

Anahtar Kavram

Solving multi-step word problems involving conversions between fractions, decimals, and percentages to find an unknown total.
Soru 317Soru

An architectural design firm is constructing a scale model of a commercial building. On the model, a rectangular conference room measures 6 inches6\text{ inches} in length and 4 inches4\text{ inches} in width. If the actual length of the conference room is 45 feet45\text{ feet}, what is the actual area, in square feet, of the conference room?

Cevabı ve açıklamayı göster

Cevap: 1,3501,350

Cevap

The actual area of the conference room is 1,3501,350 square feet.
To find the actual area, first set up a proportion using the ratio of model length to actual length (6 inches:45 feet6\text{ inches} : 45\text{ feet}). Solving 645=4w\frac{6}{45} = \frac{4}{w} gives 6w=1806w = 180, so the actual width is w=30 feetw = 30\text{ feet}. Multiplying the actual length (45 feet45\text{ feet}) by the actual width (30 feet30\text{ feet}) gives the total area of 1,350 square feet1,350\text{ square feet}.

Adım Adım Çözüm

1
Determine the linear scale factor between the model and the actual building.
The ratio of length is 6 inches:45 feet6\text{ inches} : 45\text{ feet}, which simplifies to 1 inch=7.5 feet1\text{ inch} = 7.5\text{ feet}.
Establishing the linear scale factor allows converting model measurements to actual dimensions.
2
Calculate the actual width of the conference room using a proportion.
\frac{6\text{ in}}{45\text{ ft}} = \frac{4\text{ in}}{w\text{ ft}} \implies 6w = 180 \implies w = 30\text{ feet}.
Corresponding linear dimensions in scale models are directly proportional.
3
Calculate the actual area of the rectangular room.
\text{Area} = 45\text{ ft} \times 30\text{ ft} = 1,350\text{ sq ft}.
The area of a rectangle is found by multiplying its length by its width.

Anahtar Kavram

Solving scale model problems by establishing linear proportions before calculating area.
Tahmini Süre:1m 15s
Soru 318Soru

A commercial bakery uses flour, sugar, and cocoa powder in a weight ratio of 5:3:25 : 3 : 2 to make a chocolate cake base. To create a specialty low-sugar version, the baker decreases the amount of sugar by 30%30\% and adds that exact reduced weight to the flour, leaving the amount of cocoa powder unchanged. What is the ratio of flour to sugar in the new specialty batch?

Cevabı ve açıklamayı göster

Cevap: 59:2159 : 21

Cevap

The ratio of flour to sugar in the new specialty batch is 59:2159 : 21.
In the original ratio 5:3:25 : 3 : 2, sugar accounts for 33 ratio units. Decreasing sugar by 30%30\% removes 30% of 3=0.930\% \text{ of } 3 = 0.9 units, leaving 30.9=2.13 - 0.9 = 2.1 units of sugar. Adding those 0.90.9 units to the original 55 units of flour increases flour to 5+0.9=5.95 + 0.9 = 5.9 units. The ratio of new flour to new sugar is 5.9:2.15.9 : 2.1, which multiplies by 1010 to yield 59:2159 : 21.

Adım Adım Çözüm

1
Determine the initial ratio units for each component.
Flour = 55 units, Sugar = 33 units, Cocoa = 22 units.
The original weight ratio given is 5:3:25 : 3 : 2.
2
Calculate the reduction in sugar and the new sugar ratio amount.
Reduction = 3×0.30=0.93 \times 0.30 = 0.9 units; New Sugar = 30.9=2.13 - 0.9 = 2.1 units.
Sugar is reduced by 30%30\% of its original proportion.
3
Add the removed weight to the flour to find the new flour ratio amount.
New Flour = 5+0.9=5.95 + 0.9 = 5.9 units.
The weight subtracted from sugar is added directly to the flour.
4
Form the new ratio of flour to sugar and simplify to whole numbers.
5.9:2.1=59:215.9 : 2.1 = 59 : 21.
Multiplying both parts of the decimal ratio 5.9:2.15.9 : 2.1 by 1010 converts it into a simple integer ratio.

Anahtar Kavram

Adjusting part-to-part ratios by applying percentage changes to individual components and simplifying fractional ratios.
Soru 319Soru

A community theater group allocates a total budget of dd dollars to purchase LED stage lighting fixtures. Each fixture costs $145\$145. If the theater group purchases exactly 1212 fixtures using the total allocated budget, which of the following equations can be solved to find dd?

Cevabı ve açıklamayı göster

Cevap: d145=12\frac{d}{145} = 12

Cevap

The equation representing this relationship is d145=12\frac{d}{145} = 12.
The total budget dd is divided equally among 1212 fixtures at $145\$145 each. Dividing the total budget dd by the unit price of $145\$145 equals the quantity of 1212 fixtures, which is correctly expressed as d145=12\frac{d}{145} = 12.

Adım Adım Çözüm

1
Identify the relationship between total cost, unit price, and quantity.
Total Budget = (Cost per Fixture) × (Number of Fixtures)
The total money spent equals the cost per unit multiplied by the number of units purchased.
2
Substitute the given values and variable into the relationship.
d=145×12d = 145 \times 12
dd represents the total budget, $145\$145 is the cost per fixture, and 1212 is the number of fixtures.
3
Rephrase as an equivalent one-step division equation.
d145=12\frac{d}{145} = 12
Dividing both sides of d=145×12d = 145 \times 12 by 145145 isolates the quantity 1212 on one side of the equation.

Anahtar Kavram

Formulating one-step equations from real-world rate scenarios
Soru 320Soru

A track and field athlete recorded the following distances, in meters, for 5 long jump trials during a training session: 5.85.8, 6.26.2, 5.55.5, 6.56.5, and 6.06.0. The coach requires the athlete to achieve an overall mean distance of exactly 6.16.1 meters across 66 trials. What distance, in meters, must the athlete jump on the 6th trial to reach this target mean?

Cevabı ve açıklamayı göster

Cevap: 6.66.6

Cevap

6.66.6 meters
To achieve a mean of 6.16.1 meters across 66 trials, the total combined distance must be 6×6.1=36.66 \times 6.1 = 36.6 meters. Summing the first 5 jump distances gives 5.8+6.2+5.5+6.5+6.0=30.05.8 + 6.2 + 5.5 + 6.5 + 6.0 = 30.0 meters. Subtracting this sum from the required total (36.630.036.6 - 30.0) yields 6.66.6 meters for the 6th trial.

Adım Adım Çözüm

1
Calculate the total distance of the first 5 trials.
5.8+6.2+5.5+6.5+6.0=30.05.8 + 6.2 + 5.5 + 6.5 + 6.0 = 30.0 meters
Finding the total distance currently accumulated is necessary to determine how much more is needed.
2
Calculate the total required distance for all 6 trials to achieve the target mean.
6×6.1=36.66 \times 6.1 = 36.6 meters
The formula for the mean is Mean=Total SumNumber of Trials\text{Mean} = \frac{\text{Total Sum}}{\text{Number of Trials}}, so Total Sum=Mean×Number of Trials\text{Total Sum} = \text{Mean} \times \text{Number of Trials}.
3
Subtract the current sum from the required total sum to find the required 6th jump distance.
36.630.0=6.636.6 - 30.0 = 6.6 meters
The difference between the required total distance and the current distance gives the necessary score on the final trial.

Anahtar Kavram

Target Mean with Missing Value
Tahmini Süre:1m 0s
ÖncekiSayfa 16 / 21Sonraki
Pre-Algebra Alıştırma Soruları — ACT — Sayfa 16 | Examkin