If Carol can finish a job in 5 hours and Steve can finish the same job in 10 hours, how many minutes will it take both of them together to finish the job?
A. 160
B. 180
C. 200
D. 210
E. 220
Answer: C
Source: Kaplan
If Carol can finish a job in 5 hours and Steve can finish the same job in 10 hours, how many minutes will it take both o
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 Brent@GMATPrepNow
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GIVEN:BTGModeratorVI wrote: ↑Mon Sep 14, 2020 8:43 amIf Carol can finish a job in 5 hours and Steve can finish the same job in 10 hours, how many minutes will it take both of them together to finish the job?
A. 160
B. 180
C. 200
D. 210
E. 220
Answer: C
Source: Kaplan
Carol can finish a job in 5 hours
Steve can finish the same job in 10 hours
A useful approach is to assign a "nice" value to the job.
We want a value that works well with the given information (5 hours and 10 hours).
So, let's say the entire job requires 10 tasks
This means Carol can complete 10 tasks in 5 hours. So, Carol's RATE = 2 tasks per hour
Similarly, Steve can complete 10 tasks in 10 hours. So, Steve's RATE = 1 tasks per hour
So their, COMBINED rate = 2 + 1 = 3 tasks per hour
How many minutes will it take both of them together to finish the job?
Time = output/rate
So, time = 10/3 = 10/3 HOURS
10/3 HOURS = (10/3)(60) MINUTES
= 200 MINUTES
Answer: C
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1/5 + 1/10 = 10/3
10/3 * 60 = 200 mins
IMO C
10/3 * 60 = 200 mins
IMO C
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 Scott@TargetTestPrep
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Solution:BTGModeratorVI wrote: ↑Mon Sep 14, 2020 8:43 amIf Carol can finish a job in 5 hours and Steve can finish the same job in 10 hours, how many minutes will it take both of them together to finish the job?
A. 160
B. 180
C. 200
D. 210
E. 220
Answer: C
The rate of Carol is 1/5 of the job per hour and Steven 1/10 of the job per hour. Therefore, the time needed for both of them together to finish the job is 1/(1/5 + 1/10) = 1/(2/10 + 1/10) = 1/(3/10) = 10/3 hours, or 10/3 x 60 = 200 minutes.
Answer: C
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