How many papers can Bill and Tim proofread in 60 minutes if

This topic has expert replies
Moderator
Posts: 426
Joined: Tue Aug 22, 2017 8:48 pm
Followed by:1 members
How many papers can Bill and Tim proofread in 60 minutes if they are working together?

(1) Bill can proofread twice as many papers as Tim in the same time period.

(2) Tim can proofread 30 fewer papers than Bill in 60 minutes.

How to determine which statement is sufficient?

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

by Jay@ManhattanReview » Sun Sep 24, 2017 9:21 pm
ardz24 wrote:How many papers can Bill and Tim proofread in 60 minutes if they are working together?

(1) Bill can proofread twice as many papers as Tim in the same time period.

(2) Tim can proofread 30 fewer papers than Bill in 60 minutes.

How to determine which statement is sufficient?
Say Bill proofread b number of papers in 60", while Tim does t in 60".

We have to find out the value of (b + t).

Statement 1: Bill can proofread twice as many papers as Tim in the same time period.

=> b = 2t. Clearly, insufficient.

Statement 2: Tim can proofread 30 fewer papers than Bill in 60 minutes.

=> t = b - 30. Clearly, insufficient.

Statement 1 & 2:

From b = 2t and t = b - 30, we get b = 60 and t = 30, thus, (b + t) = 90 papers. Sufficient.

The correct answer: C

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Hyderabad | Mexico City | Toronto | and many more...

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