It is currently 24 Jun 2017, 19:18

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Machine A can complete a certain job in x hours. Machine B

Author Message
Manager
Joined: 07 May 2007
Posts: 178
Machine A can complete a certain job in x hours. Machine B [#permalink]

### Show Tags

16 Jul 2007, 17:25
00:00

Difficulty:

(N/A)

Question Stats:

100% (03:06) correct 0% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Machine A can complete a certain job in x hours. Machine B can complete the same job in y hours.
If A and B work together at their respective rates to complete the job, which of the following
represents the fraction of the job that B will not have to complete because of A's help?

a) (x-y)/(x+y)
b) x/(y-x)
c) (x+y)/xy
d) y/(x-y)
e) y/(x+y)
Intern
Joined: 06 Apr 2007
Posts: 22

### Show Tags

16 Jul 2007, 21:54
A: 1/x B: 1/y

1/x + 1/y = x+y/xy

(1/x) / [(x+y)/xy] = y/x+y

(E)
16 Jul 2007, 21:54
Display posts from previous: Sort by