John and Fawn, each drinking at a constant pace, can finish

This topic has expert replies
Moderator
Posts: 2237
Joined: Sun Oct 29, 2017 2:08 pm
Followed by:2 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Manhattan Prep

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

OA B

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 » Mon Dec 24, 2018 3:18 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

AAPL wrote:Manhattan Prep

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

OA B
Say John alone takes x hours and Fawn takes y hours to finish a can.

Thus, we have 1/x + 1/y = 1/12

We have to get the value of x.

Let's take each statement one by one.

1) The average time it would take both to finish independently is 30 hours.

=> (x + y)/2 = 30 => x + y = 60

From 1/x + 1/y = 1/12, we have (x + y)/xy = 12 => xy = 720. Can't get the unique value of x. Insufficient.

2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

=> x = 10 + y

From 1/x + 1/y = 1/12, we have From 1/(y + 10) + 1/y = 1/12, we have y = 20. Thus, x = 10 + 20 = 30 hours. Sufficient.

The correct answer is B.

Either this question is not posted correctly or not drafted well. Indeed the correct answer is B, but the information from both the statements are inconsistent. From statement 2, we have the average time it would take both to finish independently = (30 + 20)/2 = 25 hours ≠ 30 hours (given in Statement 1).

A genuine GMAT question would present is a holistic situation in which the question narration, Statement 1 and Statement 2 are consistent with each other or do not contradict. To correct this, Statement 1 should be: The average time it would take both to finish independently is 25 hours.

Hope this helps!

-Jay
_________________
Manhattan Review

Locations: Manhattan Review Hyderabad | GMAT Prep Bangalore | GRE Prep Chennai | Himayatnagar GRE Coaching | and many more...

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