Question

Difficulty: HardFraction Addition and Subtraction in Context

A contractor is assigned a specialized repair project with a labor budget of 121212 \frac{1}{2} hours. The contractor works 3343 \frac{3}{4} hours on Monday, 2582 \frac{5}{8} hours on Tuesday, and 44 hours and 1010 minutes on Wednesday. If no other time is spent on the project, how many hours of the budgeted time remain?

  1. A
    21402 \frac{1}{40}
  2. B
    10132410 \frac{13}{24}
  3. 123241 \frac{23}{24}Answer
  4. D
    33

Answer

The remaining time on the project budget is 123241 \frac{23}{24} hours.
To find the remaining time, first convert all time spent into fractions of an hour with a common denominator, sum them up, and subtract the total from the budgeted hours. Converting 10 minutes to a fraction of an hour yields 10/60=1/610/60 = 1/6 hour. The sum of the fractions is 334+258+4163 \frac{3}{4} + 2 \frac{5}{8} + 4 \frac{1}{6}. The lowest common denominator for 4, 8, and 6 is 24. Converting the fractions gives 31824+21524+4424=937243 \frac{18}{24} + 2 \frac{15}{24} + 4 \frac{4}{24} = 9 \frac{37}{24}, which simplifies to 10132410 \frac{13}{24} hours. Subtracting this from the budget requires regrouping: 121224−101324=113624−101324=1232412 \frac{12}{24} - 10 \frac{13}{24} = 11 \frac{36}{24} - 10 \frac{13}{24} = 1 \frac{23}{24} hours.

Step-by-Step Solution

1
Convert the time worked on Wednesday into a mixed number with a fraction of an hour.
44 hours and 1010 minutes = 410604 \frac{10}{60} hours = 4164 \frac{1}{6} hours.
All quantities must be in the same unit (hours) and fraction format before adding.
2
Find a common denominator to add the hours worked on Monday, Tuesday, and Wednesday.
The lowest common denominator for 44, 88, and 66 is 2424. The fractions become 318243 \frac{18}{24}, 215242 \frac{15}{24}, and 44244 \frac{4}{24}.
Fractions can only be added when they share a common denominator.
3
Add the converted fractions to find the total time spent.
31824+21524+4424=937243 \frac{18}{24} + 2 \frac{15}{24} + 4 \frac{4}{24} = 9 \frac{37}{24}. Since 3724=11324\frac{37}{24} = 1 \frac{13}{24}, the total is 10132410 \frac{13}{24} hours.
Adding the individual shifts gives the combined total hours worked so far.
4
Subtract the total time spent from the budgeted time to find the remaining hours.
1212−101324=121224−10132412 \frac{1}{2} - 10 \frac{13}{24} = 12 \frac{12}{24} - 10 \frac{13}{24}. Regrouping 12122412 \frac{12}{24} gives 11362411 \frac{36}{24}. Subtracting yields 113624−101324=1232411 \frac{36}{24} - 10 \frac{13}{24} = 1 \frac{23}{24} hours.
Subtracting the part used from the whole budget determines the remaining balance.

Key Concept

Adding and subtracting mixed numbers with unlike denominators in real-world contexts, including unit conversions and regrouping.
Estimated Time:2m 30s
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