BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the same

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the same

by BTGmoderatorDC » Wed Jun 03, 2020 6:57 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the same job in 12 hours. If they work together for 2 hours, how many minutes will it take Sam to finish the job, working alone at his constant rate?

A. 5
B. 20
C. 30
D. 60
E. 120


OA C

Source: Princeton Review
Top
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: Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the s

by Jay@ManhattanReview » Wed Jun 03, 2020 10:46 pm
BTGmoderatorDC wrote: ↑
Wed Jun 03, 2020 6:57 pm
 Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the same job in 12 hours. If they work together for 2 hours, how many minutes will it take Sam to finish the job, working alone at his constant rate?

A. 5
B. 20
C. 30
D. 60
E. 120

OA C

Source: Princeton Review
Given the information, Sam can work 1/3 part of the work in 1 hour or 2/3 part of the work in 2 hours; similarly, Mark can work 1/12 part of the work in 1 hour or 2/12 = 1/6 part of the work in 2 hours.

Thus, in 2 hours they together finish 2/3 + 1/6 = 5/6 part of the work.

Thus, the work left to be done = 1 – 5/6 = 1/6

Since San can do 1/3 part of the work in 1 work, he can do 1/6 part of the work in 1/2 hour or 30 min.

The correct answer: C

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: GMAT Classes Albuquerque | GMAT Tutoring | GRE Prep Courses El Paso | Oakland Prep Classes SAT | and many more...

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

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

Re: Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the s

by Scott@TargetTestPrep » Sat Apr 03, 2021 10:30 am
BTGmoderatorDC wrote: ↑
Wed Jun 03, 2020 6:57 pm
 Working at a constant rate, Sam can finish a job in 3 hours. Mark, also working at a constant rate, can finish the same job in 12 hours. If they work together for 2 hours, how many minutes will it take Sam to finish the job, working alone at his constant rate?

A. 5
B. 20
C. 30
D. 60
E. 120


OA C

Solution:

The rate of Sam is 1/3 and the rate of Mark is 1/12. We can let Sam’s time = 2 + x hours and Mark’s time = 2 hours; thus:

(1/3)(2 + x) + (1/12)(2) = 1

(2 + x)/3 + 1/6 = 1

Multiplying the equation by 6, we have:

4 + 2x + 1 = 6

2x = 1

x = 1/2 hour = 30 minutes

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Post new topic Post Reply
• Page 1 of 1