Work/Rate Problems

This topic has expert replies
Legendary Member
Posts: 2499
Joined: Sun Oct 29, 2017 2:04 pm
Followed by:6 members

Work/Rate Problems

by swerve » Mon Jul 20, 2020 11:42 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Three machines operating independently, simultaneously, and at the same constant rate can fill a certain production order in 36 hours. If one additional machine were used under the same operating conditions, in how many fewer hours of simultaneous operation could the production order be fulfilled?

A. 6
B. 9
C. 12
D. 27
E. 48

The OA is B

Source: GMAT Prep
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

Re: Work/Rate Problems

by Jay@ManhattanReview » Tue Jul 21, 2020 4:06 am
swerve wrote:
Mon Jul 20, 2020 11:42 am
Three machines operating independently, simultaneously, and at the same constant rate can fill a certain production order in 36 hours. If one additional machine were used under the same operating conditions, in how many fewer hours of simultaneous operation could the production order be fulfilled?

A. 6
B. 9
C. 12
D. 27
E. 48

The OA is B

Source: GMAT Prep
Given that three machines operating independently, simultaneously, and at the same constant rate can fill a certain production order in 36 hours, one machine can do the same work in 36*3 = 108 hours.

Thus, 4 similar machines would do the 108-hour work in 108/4 = 27 hours.

Saving in time = 36 – 27 = 9 hours

Correct answer: B

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: GMAT Prep | ACT Prep | TOEFL Prep | IELTS Prep | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.