A work crew of 4 Men

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by BTGmoderatorDC » Thu Jan 04, 2018 11:58 pm

A work crew of 4 Men takes 5 days to complete one-half of a job. If 6 men are then added to the crew and the men continue to work at the same rate, how many days will it take the enlarged crew to do the rest of the job?

A. 2
B. 3
C. 3 1/3
D. 4
E. 4 4/5

How will i solve this kind of problem?

OA A

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Source: Beat The GMAT — Problem Solving | Thu Jan 04, 2018 11:58 pm

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by GMATGuruNY » Fri Jan 05, 2018 12:10 am

lheiannie07 wrote:A work crew of 4 Men takes 5 days to complete one-half of a job. If 6 men are then added to the crew and the men continue to work at the same rate, how many days will it take the enlarged crew to do the rest of the job?

A. 2
B. 3
C. 3 1/3
D. 4
E. 4 4/5

The amount of work is the same for each half of the job, enabling us to use the following formula:
(workers)(time) = (workers)(time).

Since 4 workers take 5 days to do half the job, and we must determine the number of days for 10 workers to do the remaining half, we get:
(4 workers)(5 days) = (10 workers)(x days)
20 = 10x
x = 2.

The correct answer is A.

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by [email protected] » Fri Jan 05, 2018 10:30 am

Hi lheiannie07,

We're told that a work crew of 4 men takes 5 days to complete one-half of a job and then 6 men are then added to the crew (and the men continue to work at the same rate). We're asked how many days it will take the larger crew to do the rest of the job.

In these types of 'Work' questions, it often helps to think in terms of the total amount of work-days that are needed to complete a task. Here, we have 4 men working for 5 days each to complete HALF of a job...
(4 men)(5 days of work each) = 20 men-days of work to complete 1/2 of a job.

Since half of the job is now done, this means that another 20 men-days of work are needed to finish the REST of the job. Adding 6 more men to the team gives us 10 men total...
(10 men)(X days of work each) = 20 men-days of work needed
X = 20/10 = 2 days of work each

Final Answer: A

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by DavidG@VeritasPrep » Fri Jan 05, 2018 11:43 am

lheiannie07 wrote:A work crew of 4 Men takes 5 days to complete one-half of a job. If 6 men are then added to the crew and the men continue to work at the same rate, how many days will it take the enlarged crew to do the rest of the job?

A. 2
B. 3
C. 3 1/3
D. 4
E. 4 4/5

How will i solve this kind of problem?

OA A

You could also just use a bit of logic and the answer choices. If we doubled the number of men working, we'd halve the time it takes to complete the job. So if 4 Men could do half a job in 5 days, 8 men could do half a job in 2.5 days. But we've got 10 men! So clearly, they can do the job faster than 8 men could. The only answer under 2.5 is A

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