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Question 2141Question →

A theater crew is building a wooden stage prop in the shape of a right triangle. The vertical height of the prop is 1212 feet and the horizontal base is 55 feet. What is the length of the slanted top edge of the prop?

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Answer: 1313 feet

Answer

The length of the slanted top edge is 1313 feet.
The slanted edge represents the hypotenuse of a right triangle. According to the Pythagorean theorem, the square of the hypotenuse equals the sum of the squares of the two perpendicular legs (a2+b2=c2a^2 + b^2 = c^2). Substituting the given legs (55 and 1212), we calculate 52+122=25+144=1695^2 + 12^2 = 25 + 144 = 169. Taking the square root of 169169 yields 1313 feet.

Step-by-Step Solution

1
Identify the given values as the legs of a right triangle.
The legs are a=5a = 5 and b=12b = 12. The unknown slanted edge is the hypotenuse, cc.
The Pythagorean theorem relates the two perpendicular legs to the longest side.
2
Substitute the leg values into the Pythagorean theorem formula, a2+b2=c2a^2 + b^2 = c^2.
52+122=c25^2 + 12^2 = c^2
This sets up the equation to solve for the missing hypotenuse.
3
Square the numbers and add them together.
25+144=c225 + 144 = c^2, which simplifies to 169=c2169 = c^2.
This isolates c2c^2 on one side of the equation.
4
Take the square root of both sides to find the value of cc.
c=13c = 13
Taking the square root cancels the exponent and gives the final length of the edge.

Key Concept

Using the Pythagorean theorem to calculate the hypotenuse of a right triangle.
Question 2142Question →

A military supply depot receives a shipment of 5,0005,000 equipment crates. Upon initial sorting, 20%20\% of the crates are assigned to the aviation unit. Of the remaining crates, 35%35\% are assigned to the infantry unit. How many crates are assigned to the infantry unit?

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Answer: 1,400

Answer

1,400
The problem requires a two-step percentage calculation. First, find the remaining crates after 20%20\% are taken from the initial 5,0005,000 crates, leaving 4,0004,000 crates. Second, calculate 35%35\% of that remaining 4,0004,000 crates, which equals 1,4001,400.

Step-by-Step Solution

1
Calculate the number of crates assigned to the aviation unit.
5,000×0.20=1,0005,000 \times 0.20 = 1,000
To find how many crates are removed from the initial shipment.
2
Subtract the aviation crates from the total to find the remaining crates.
5,000−1,000=4,0005,000 - 1,000 = 4,000
The infantry receives a percentage of the remaining crates, not the original total.
3
Calculate the number of crates assigned to the infantry unit from the remaining amount.
4,000×0.35=1,4004,000 \times 0.35 = 1,400
This answers the specific question asked.

Key Concept

Calculating percentages of a remaining quantity in a multi-step scenario.

Alternative Method

Instead of calculating the 20%20\% and subtracting, you can find the remaining percentage directly: 100%−20%=80%100\% - 20\% = 80\%. Then, 5,000×0.80=4,0005,000 \times 0.80 = 4,000. Finally, 4,000×0.35=1,4004,000 \times 0.35 = 1,400.
Estimated Time:1m 0s
Question 2143Question →

A circular hatch on a maritime vessel has a diameter of 1414 inches. What is the area of the hatch in square inches?

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Answer: 49π49\pi

Answer

The correct area is 49π49\pi square inches.
The correct answer is found by first determining the radius, which is half of the given diameter (14÷2=714 \div 2 = 7 inches). Applying the area formula A=πr2A = \pi r^2 yields π×72=49π\pi \times 7^2 = 49\pi square inches.

Step-by-Step Solution

1
Determine the radius of the circular hatch.
Radius = 14÷2=714 \div 2 = 7 inches.
The formula for the area of a circle requires the radius, which is exactly half of the diameter.
2
Apply the area formula for a circle.
Area = π×72=49π\pi \times 7^2 = 49\pi square inches.
The area of a circle is found using the formula A=πr2A = \pi r^2.

Key Concept

Calculating the area of a circle by first deriving the radius from the diameter.
Question 2144Question →

A radar operator tracks the number of aircraft detected in their sector during 55 consecutive hours. The hourly counts are 2424, 1818, 3535, 2121, and 1212. What is the median number of aircraft detected per hour?

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Answer: 2121

Answer

The median number of aircraft detected per hour is 2121.
The median is found by arranging the values in ascending order (1212, 1818, 2121, 2424, 3535) and identifying the middle value. The middle number is 2121.

Step-by-Step Solution

1
Order the hourly aircraft counts from least to greatest.
1212, 1818, 2121, 2424, 3535
The median is the middle value of an ordered dataset.
2
Identify the middle number in the sorted sequence.
The third number is 2121.
Since there are 55 data points (an odd number), the median is exactly in the middle.

Key Concept

The median is the middle value of a sorted dataset. If a dataset has an odd number of values, the median is the single middle number.
Question 2145Question →

A high-speed passenger train is scheduled to travel a 300300-mile route between two cities with an overall average speed of 6060 miles per hour. During the first leg of the trip, the train travels 150150 miles at an average speed of 5050 miles per hour. At what average speed must the train travel for the remaining 150150 miles to meet its scheduled overall average speed?

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Answer: 75 mph

Answer

The train must travel at 75 mph for the remaining distance.
To solve for the required speed, you must work with time. The entire 300-mile trip at an average of 60 mph allows a total of 5 hours (300÷60=5300 \div 60 = 5). The first 150 miles at 50 mph consumed 3 hours (150÷50=3150 \div 50 = 3). This leaves exactly 2 hours to cover the remaining 150 miles. Dividing the remaining distance by the remaining time (150÷2150 \div 2) gives the necessary speed of 75 mph.

Step-by-Step Solution

1
Calculate the total time allowed for the entire trip.
300 miles÷60 mph=5 hours300 \text{ miles} \div 60 \text{ mph} = 5 \text{ hours}
Average speed is defined as total distance divided by total time. We need the total time limit to figure out how much time is left.
2
Calculate the time spent on the first leg of the trip.
150 miles÷50 mph=3 hours150 \text{ miles} \div 50 \text{ mph} = 3 \text{ hours}
Using the distance and speed given for the first segment, we determine how much of our total time budget has been used.
3
Determine the time remaining for the second leg.
5 hours−3 hours=2 hours5 \text{ hours} - 3 \text{ hours} = 2 \text{ hours}
Subtracting the time already used from the total allowed time gives the time remaining to complete the journey.
4
Calculate the required average speed for the remaining distance.
150 miles÷2 hours=75 mph150 \text{ miles} \div 2 \text{ hours} = 75 \text{ mph}
Speed is distance divided by time. Applying this to the remaining segment gives the required speed.

Key Concept

To find an unknown speed in a multi-segment trip, you must base calculations on Total Distance and Total Time, rather than averaging the individual speeds.
Question 2146Question →

Match each circular geometry scenario with its corresponding simplified algebraic expression.

Click a left item, then click its matching right item

Items

The area of a circular pathway of uniform width xx surrounding a pool with radius rr
The total perimeter of a semicircular window with radius rr
The number of full revolutions a tire with diameter dd makes to travel a distance DD
The radius of a circle whose area is exactly half the area of a circle with radius RR

Matches

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Answer

The correct pairings connect each geometric scenario to its simplified algebraic derivation by applying circle formulas, expanding binomials, and rationalizing denominators.
Each expression is correctly derived by applying the fundamental formulas for circle area and circumference, followed by rigorous algebraic simplification such as factoring, binomial expansion, or radical rationalization.

Step-by-Step Solution

1
Analyze the annular pathway area scenario.
πx(2r+x)\pi x(2r + x)
Requires subtracting the inner pool area from the total outer area and expanding the squared binomial (r+x)2(r+x)^2.
2
Determine the semicircular perimeter expression.
r(π+2)r(\pi + 2)
Requires adding the semicircular arc length to the straight diameter base and factoring out the radius.
3
Calculate the algebraic expression for tire revolutions.
Dπd\frac{D}{\pi d}
Requires dividing the total linear distance by the circumference of the tire, utilizing the diameter.
4
Solve for the half-area radius.
R22\frac{R\sqrt{2}}{2}
Requires setting up an area ratio equation, solving for the new radius, and rationalizing the denominator of the resulting square root.

Key Concept

Algebraic representation and derivation of advanced circular measurements
Question 2147Question →

A rectangular garden gate needs a diagonal wooden brace for support. The gate is 44 feet tall and 33 feet wide. What is the length, in feet, of the diagonal brace?

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Answer: 5

Answer

5
The diagonal brace forms the hypotenuse of a right triangle where the width (33 feet) and height (44 feet) are the legs. According to the Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2), we substitute the given lengths: 32+42=c23^2 + 4^2 = c^2. This simplifies to 9+16=259 + 16 = 25. Taking the square root of 2525 gives a diagonal length of 55 feet. This forms a common 3−4−53-4-5 Pythagorean triple.

Step-by-Step Solution

1
Identify the right triangle formed by the gate
The legs of the right triangle are 33 and 44, and the hypotenuse is the unknown diagonal brace.
The corners of a rectangular gate form right angles, so drawing a diagonal creates a right triangle.
2
Apply the Pythagorean theorem
32+42=c23^2 + 4^2 = c^2
The Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2) is used to find the missing side length of a right triangle.
3
Calculate the squares of the legs
9+16=c29 + 16 = c^2
Squaring the given lengths prepares the equation for addition.
4
Solve for the hypotenuse
25=c225 = c^2, which means c=5c = 5
Taking the square root of the sum yields the length of the diagonal brace.

Key Concept

Using the Pythagorean theorem to find the hypotenuse of a right triangle.
Question 2148Question →

A piece of wire is bent to form a square with an area of 144144 square centimeters. If the same wire is straightened and then bent to form a rectangle whose length is 44 centimeters longer than its width, what is the area of this new rectangle?

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Answer: 140140 square centimeters

Answer

140140 square centimeters
First, find the side length of the square. Since the area is 144144, the side length is 144=12\sqrt{144} = 12. The total length of the wire is the perimeter of the square, which is 12×4=4812 \times 4 = 48. This wire is then used to form a rectangle, so the rectangle's perimeter is also 4848. Let the width of the rectangle be WW. The length is W+4W + 4. The perimeter formula is 2(L+W)=P2(L + W) = P. Substituting the values gives 2(W+W+4)=482(W + W + 4) = 48, which simplifies to 4W+8=484W + 8 = 48. Solving for WW yields 4W=404W = 40, so W=10W = 10. The length is 10+4=1410 + 4 = 14. The area of the new rectangle is 10×14=14010 \times 14 = 140 square centimeters.

Step-by-Step Solution

1
Calculate the total length of the wire using the square's area.
The side of the square is 144=12\sqrt{144} = 12 cm. The perimeter is 12×4=4812 \times 4 = 48 cm.
The total length of the wire remains constant and equals the perimeter of both shapes.
2
Set up an equation for the rectangle's perimeter.
Let width be WW. Length is W+4W + 4. The perimeter is 2(W+(W+4))=482(W + (W + 4)) = 48.
The rectangle is made from the same wire, so its perimeter is 4848 cm, and its length is 44 cm longer than its width.
3
Solve for the width (WW) and length (LL) of the rectangle.
2(2W+4)=48⇒4W+8=48⇒4W=40⇒W=102(2W + 4) = 48 \Rightarrow 4W + 8 = 48 \Rightarrow 4W = 40 \Rightarrow W = 10 cm. The length is 10+4=1410 + 4 = 14 cm.
Solving the linear equation provides the dimensions needed to find the area.
4
Calculate the area of the rectangle.
Area = 10×14=14010 \times 14 = 140 square centimeters.
The area of a rectangle is its length multiplied by its width.

Key Concept

Perimeter and Area of 2D Figures
Question 2149Question →

A rectangular shipping crate has a length of 66 feet, a width of 44 feet, and a height of 33 feet. What is the volume of the crate in cubic feet?

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Answer: 72

Answer

72
The volume of a rectangular prism is calculated by multiplying its length, width, and height. Multiplying 66 feet by 44 feet by 33 feet results in exactly 7272 cubic feet.

Step-by-Step Solution

1
Recall the volume formula for a rectangular prism.
V=l×w×hV = l \times w \times h
To find the volume, we must multiply the length, width, and height of the 3D figure.
2
Substitute the given dimensions into the formula.
V=6×4×3V = 6 \times 4 \times 3
The problem states the length is 66 feet, the width is 44 feet, and the height is 33 feet.
3
Multiply the values to find the total volume.
V=24×3=72V = 24 \times 3 = 72
Completing the arithmetic gives the final volume in cubic feet.

Key Concept

Volume of a Rectangular Prism
Question 2150Question →

A base defense unit receives a shipment of 7,5007,500 sandbags to reinforce security perimeters. If 18%18\% of the sandbags are deployed to the north gate and 34%34\% are deployed to the east gate, how many sandbags remain in the reserve depot?

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Answer: 3600

Answer

There are 3,600 sandbags remaining in the reserve depot.
The correct answer is found by first determining the total percentage of sandbags allocated to the gates, which is 18%+34%=52%18\% + 34\% = 52\%. Subtracting this from the total 100%100\% leaves 48%48\% for the reserve depot. Multiplying 0.480.48 by the initial 7,5007,500 sandbags gives the final remaining amount of 3,6003,600 sandbags.

Step-by-Step Solution

1
Calculate the total percentage of deployed sandbags.
18%+34%=52%18\% + 34\% = 52\%
This consolidates the parts of the whole that have already been allocated.
2
Determine the percentage of sandbags that remain.
100%−52%=48%100\% - 52\% = 48\%
Subtracting the allocated portion from the total whole (100%) gives the remaining fraction.
3
Calculate 48% of the initial 7,500 sandbags.
0.48×7500=36000.48 \times 7500 = 3600
This translates the remaining percentage back into a specific physical quantity.

Key Concept

Calculating the remaining percentage of a quantity by subtracting the used percentages from 100%100\%, then multiplying by the original total.
Question 2151Question →

A kite designer is creating a kite in the shape of a rhombus. The two crossing wooden dowels that form the internal diagonals of the kite measure 1616 inches and 3030 inches. What is the total perimeter of the kite's outer edge, in inches?

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Answer: 68

Answer

68
The correct answer is found by recognizing that a rhombus's diagonals bisect each other perpendicularly. This allows the use of the Pythagorean theorem with half-diagonal lengths (88 and 1515) to find a side length of 1717. Multiplying this single side length by the four equal sides of the rhombus yields a total perimeter of 6868 inches.

Step-by-Step Solution

1
Determine the properties of the diagonals in a rhombus.
The diagonals bisect each other at right angles, forming four identical right triangles.
This breaks down the rhombus into simpler geometric shapes (right triangles), allowing for side length calculation.
2
Calculate the lengths of the legs for one of the right triangles.
The legs are 88 inches (16÷216 \div 2) and 1515 inches (30÷230 \div 2).
The diagonals cut each other exactly in half at the intersection.
3
Use the Pythagorean theorem to find the length of the rhombus's outer edge.
The side length is 82+152=64+225=289=17\sqrt{8^2 + 15^2} = \sqrt{64 + 225} = \sqrt{289} = 17 inches.
The outer edge forms the hypotenuse of the right triangle created by the half-diagonals.
4
Calculate the total perimeter.
17×4=6817 \times 4 = 68 inches.
A rhombus has four equal sides, so the total perimeter is four times the length of one side.

Key Concept

Perimeter of a Rhombus and Pythagorean Theorem
Question 2152Question →

A military supply convoy is tasked with delivering equipment to an outpost 210210 miles away. The convoy commander is ordered to maintain an overall average speed of 3535 miles per hour for the entire journey. If the convoy completes the first 9090 miles in 22 hours, what average speed, in miles per hour, must they maintain for the remainder of the trip to exactly meet their overall time target?

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Answer: 30

Answer

The convoy must maintain a speed of 30 mph for the remainder of the trip.
The overall target requires the 210210-mile trip to be completed in 66 hours (210÷35210 \div 35). Because the first 9090 miles took 22 hours, there are 120120 miles left to travel and 44 hours remaining to do so. Therefore, the required speed is 120120 miles ÷\div 44 hours = 3030 mph.

Step-by-Step Solution

1
Calculate the total allowable time for the convoy's trip.
Total time = 210÷35=6210 \div 35 = 6 hours.
Overall average speed is the total distance divided by total time. Knowing the total distance and target average speed allows us to find the total time allowed.
2
Calculate the remaining distance for the second part of the trip.
Remaining distance = 210−90=120210 - 90 = 120 miles.
We need to find out how much further the convoy has to travel.
3
Calculate the remaining time available to complete the journey.
Remaining time = 6−2=46 - 2 = 4 hours.
Subtracting the time already spent from the total time gives the time left to cover the remaining distance.
4
Calculate the required average speed for the final leg.
Required speed = 120÷4=30120 \div 4 = 30 mph.
Average speed for any leg is the distance of that leg divided by the time spent on that leg.

Key Concept

Average speed is calculated by dividing the total distance by the total time, and the properties of individual legs (distance and time) sum to the total distance and total time.
Question 2153Question →

A recruiting station commander records the number of new applicants processed each day for 55 consecutive days. The daily counts are 33, 33, 55, 88, and 1111. Match each measure of central tendency to its correct calculated value for this data set.

Click a left item, then click its matching right item

Items

Mode
Median
Mean

Matches

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Answer

The correct matches are: Mode pairs with 33, Median pairs with 55, and Mean pairs with 66.
Based on the data set of 3,3,5,8,113, 3, 5, 8, 11, the mode is 33 because it appears most frequently. The median is 55 because it is the central value of the ordered list. The mean is 66 because the sum (3030) divided by the count (55) equals 66.

Step-by-Step Solution

1
Determine the mode of the data set.
Mode = 33
The mode is the number that appears most frequently. 33 is the only number that appears more than once.
2
Determine the median of the data set.
Median = 55
The data is already arranged in ascending order: 3,3,5,8,113, 3, 5, 8, 11. The middle number (third position out of five) is 55.
3
Calculate the mean of the data set.
Mean = 66
Calculate the sum of the numbers (3+3+5+8+11=303 + 3 + 5 + 8 + 11 = 30) and divide by the number of days (55): 30÷5=630 \div 5 = 6.

Key Concept

Calculating the primary measures of central tendency (mean, median, and mode) for a data set.
Estimated Time:45s
Question 2154Question →

A game at a school carnival involves drawing two wooden blocks from a bag without looking. The bag initially contains 9 red blocks, 7 yellow blocks, and 5 blue blocks. If a player draws two blocks one after the other without replacing the first block, what is the probability that the first block drawn is blue and the second block drawn is yellow?

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Answer: 112\frac{1}{12}

Answer

112\frac{1}{12}
The correct answer is found by multiplying the probability of the first event by the probability of the second event, accounting for the reduced total pool. The probability of drawing a blue block first is 521\frac{5}{21}. Because this block is not replaced, only 20 blocks remain in the bag. The probability of then drawing a yellow block is 720\frac{7}{20}. Multiplying these probabilities gives 521×720=35420\frac{5}{21} \times \frac{7}{20} = \frac{35}{420}, which simplifies to 112\frac{1}{12}.

Step-by-Step Solution

1
Calculate the total number of blocks initially in the bag.
9 (red)+7 (yellow)+5 (blue)=21 total blocks9 \text{ (red)} + 7 \text{ (yellow)} + 5 \text{ (blue)} = 21 \text{ total blocks}
The denominator for the first probability requires the total count of all possible outcomes.
2
Determine the probability of the first event (drawing a blue block).
521\frac{5}{21}
There are 5 blue blocks out of the 21 total blocks.
3
Determine the probability of the second event (drawing a yellow block) given that a blue block was already removed.
720\frac{7}{20}
Because the first block was not replaced, there are now 21−1=2021 - 1 = 20 total blocks. There are still 7 yellow blocks in the bag.
4
Multiply the probabilities of the two dependent events and simplify.
521×720=35420=112\frac{5}{21} \times \frac{7}{20} = \frac{35}{420} = \frac{1}{12}
To find the compound probability of both events occurring in sequence, you must multiply their individual probabilities.

Key Concept

Dependent Compound Probability
Question 2155Question →

A cylindrical canister has a radius of 33 inches and a height of 55 inches. Which of the following represents the total volume of the canister in cubic inches?

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Answer: 45π45\pi

Answer

45π45\pi
The correct answer is 45π45\pi. The volume of a cylinder is found using the formula V=πr2hV = \pi r^2 h. Squaring the given radius of 33 results in 99. Multiplying 99 by the given height of 55 yields 45π45\pi cubic inches.

Step-by-Step Solution

1
Identify the correct formula for the volume of a cylinder.
V=πr2hV = \pi r^2 h
The question asks for the volume of a cylindrical shape.
2
Substitute the given values into the formula.
V=π(3)2(5)V = \pi (3)^2 (5)
The radius (r) is 3 inches and the height (h) is 5 inches.
3
Square the radius according to the order of operations.
32=93^2 = 9
Exponents must be evaluated before multiplication.
4
Multiply the squared radius by the height and pi.
9×5×π=45π9 \times 5 \times \pi = 45\pi
This completes the volume calculation.

Key Concept

Volume of a Cylinder
Question 2156Question →

In a right triangle, the two shorter sides (legs) measure 1010 inches and 2424 inches. What is the length of the hypotenuse in inches?

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Answer: 26

Answer

The length of the hypotenuse is 26 inches.
The hypotenuse is found by applying the Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2). When you square the given legs (1010 and 2424), you get 100100 and 576576. Adding these gives 676676. Finally, taking the square root of 676676 results in 2626. This is also recognized as a scaled version of the fundamental 5-12-13 Pythagorean triple (multiplied by 2).

Step-by-Step Solution

1
Recall the Pythagorean theorem formula.
a2+b2=c2a^2 + b^2 = c^2
This formula connects the lengths of the legs (aa and bb) to the hypotenuse (cc) in a right triangle.
2
Substitute the given leg lengths into the formula.
102+242=c210^2 + 24^2 = c^2
The lengths of the two shorter sides are given as 10 and 24.
3
Square the lengths of the legs.
100+576=c2100 + 576 = c^2
Following the order of operations, evaluate the exponents before adding.
4
Add the squared values together.
676=c2676 = c^2
Combine the values to find the square of the hypotenuse.
5
Take the square root of both sides to solve for c.
c=676=26c = \sqrt{676} = 26
Taking the square root provides the final length of the hypotenuse.

Key Concept

Pythagorean Theorem
Question 2157Question →

A sonar technician records the number of acoustic anomalies detected during 55 consecutive watch shifts. The counts are 7,2,8,27, 2, 8, 2, and 66. What is the median number of anomalies detected per shift?

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Answer: 6

Answer

6
To find the median, the values must first be ordered from least to greatest: 2,2,6,7,82, 2, 6, 7, 8. Because there is an odd number of values (55), the median is the single middle number. The third number in this sorted list is 66.

Step-by-Step Solution

1
Order the given numbers from least to greatest.
2,2,6,7,82, 2, 6, 7, 8
The median must always be found from a sorted list of values.
2
Identify the middle value in the sorted list.
Since there are 55 values, the middle value is the 33 rd number, which is 66.
For an odd number of data points, the median is exactly the single middle number.

Key Concept

The median is the middle value of a data set when the numbers are arranged in numerical order.
Question 2158Question →

Calculate the solution (x,y)(x, y) for the system of linear equations shown below.

3x−2y=73x - 2y = 7
2x+4y=102x + 4y = 10

What is the value of the expression x−yx - y?

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Answer: 2

Answer

The correct value of the expression is 2.
The system can be efficiently solved using either substitution or elimination. By dividing the second equation by 2, we get x+2y=5x + 2y = 5, which means x=5−2yx = 5 - 2y. Substituting this into the first equation gives 3(5−2y)−2y=73(5 - 2y) - 2y = 7. Distributing the 3 results in 15−6y−2y=715 - 6y - 2y = 7, which simplifies to 15−8y=715 - 8y = 7. Subtracting 15 from both sides gives −8y=−8-8y = -8, so y=1y = 1. Substituting y=1y = 1 back into x=5−2yx = 5 - 2y yields x=5−2(1)=3x = 5 - 2(1) = 3. Finally, the requested expression is x−yx - y, which evaluates to 3−1=23 - 1 = 2.

Step-by-Step Solution

1
Simplify the second equation by dividing all terms by 2.
x+2y=5x + 2y = 5
Dividing the entire equation by a common factor makes the coefficients smaller and allows us to easily isolate xx for the substitution method.
2
Isolate xx in the simplified equation.
x=5−2yx = 5 - 2y
Expressing xx in terms of yy prepares us to substitute this expression into the first equation.
3
Substitute the expression for xx into the first equation and solve for yy.
3(5−2y)−2y=7⇒15−6y−2y=7⇒15−8y=7⇒−8y=−8⇒y=13(5 - 2y) - 2y = 7 \Rightarrow 15 - 6y - 2y = 7 \Rightarrow 15 - 8y = 7 \Rightarrow -8y = -8 \Rightarrow y = 1
This step eliminates xx entirely, creating a single-variable linear equation that can be solved to find the exact value of yy.
4
Substitute the value of yy back into the isolated xx equation to find xx.
x=5−2(1)⇒x=5−2⇒x=3x = 5 - 2(1) \Rightarrow x = 5 - 2 \Rightarrow x = 3
Now that we have the numerical value for yy, we can plug it back in to find the corresponding value for xx.
5
Evaluate the final expression x−yx - y using the calculated values.
3−1=23 - 1 = 2
The question asks specifically for the value of x−yx - y, not just the ordered pair.

Key Concept

To solve a system of linear equations, you can use substitution by isolating a variable in one equation and substituting it into the other, or use elimination by combining the equations to cancel out a variable.
Question 2159Question →

An aviation squadron is allotted a total of 12,00012,000 flight hours for the training year. During the first quarter, the squadron uses 28%28\% of its total allotted hours. During the second quarter, it uses an additional 35%35\% of the total allotted hours. How many flight hours remain for the rest of the year?

Show answer & explanation

Answer: 4,4404,440

Answer

The squadron has 4,4404,440 flight hours remaining.
The total percentage of flight hours used in the first two quarters is the sum of 28%28\% and 35%35\%, which equals 63%63\%. To find the remaining percentage, subtract this from 100%100\%, leaving 37%37\%. Finally, to find the exact number of hours left, calculate 37%37\% of the total 12,00012,000 hours by multiplying 12,00012,000 by 0.370.37, which results in 4,4404,440 hours.

Step-by-Step Solution

1
Add the percentages of flight hours used in the first and second quarters.
28%+35%=63%28\% + 35\% = 63\%
This determines the total percentage of the allotted hours that have already been consumed.
2
Subtract the total used percentage from 100%100\% to find the remaining percentage.
100%−63%=37%100\% - 63\% = 37\%
This represents the percentage of the total flight hours that are still available for the rest of the year.
3
Calculate 37%37\% of the total 12,00012,000 flight hours.
0.37×12,000=4,4400.37 \times 12,000 = 4,440
Converting the remaining percentage to a decimal and multiplying it by the total allocation yields the actual number of remaining hours.

Key Concept

Calculating Percentages of Quantities
Question 2160Question →

A navigation briefcase contains 1515 identical-looking USB drives. 99 of the drives contain map data, and 66 contain communication protocols. If a pilot randomly selects two drives from the briefcase one after the other without replacing the first, what is the probability that both selected drives contain map data? Express your answer as a simplified fraction.

Show answer & explanation

Answer: 12/35; 12 / 35

Answer

12/35
The correct answer is derived by multiplying the initial probability of drawing a map drive (915\frac{9}{15}) by the updated probability of drawing a second map drive from the remaining inventory (814\frac{8}{14}). Simplifying the fractions to 35\frac{3}{5} and 47\frac{4}{7} before multiplying gives the final result of 1235\frac{12}{35}.

Step-by-Step Solution

1
Determine the probability of selecting a map data drive on the first draw.
P(First Map) = 99 map drives / 1515 total drives = 915=35\frac{9}{15} = \frac{3}{5}.
The probability of a single event is the number of favorable outcomes divided by the total number of possible outcomes.
2
Determine the probability of selecting a map data drive on the second draw, given that one map drive has already been removed.
P(Second Map) = 88 map drives remaining / 1414 total drives remaining = 814=47\frac{8}{14} = \frac{4}{7}.
Since the first drive is not replaced, both the number of map drives and the total number of drives decrease by one. This is a dependent event.
3
Calculate the compound probability of both dependent events occurring.
35×47=1235\frac{3}{5} \times \frac{4}{7} = \frac{12}{35}.
To find the probability of two dependent events happening in sequence, you multiply the probability of the first event by the conditional probability of the second event.

Key Concept

Compound probability of dependent events (without replacement)
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