A work crew of 4 Men

This topic has expert replies
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

A work crew of 4 Men

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

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

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.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

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

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image

User avatar
Legendary Member
Posts: 2663
Joined: Wed Jan 14, 2015 8:25 am
Location: Boston, MA
Thanked: 1153 times
Followed by:128 members
GMAT Score:770

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
Veritas Prep | GMAT Instructor

Veritas Prep Reviews
Save $100 off any live Veritas Prep GMAT Course