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

Redeem

pt question

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 141
Joined: Wed Mar 28, 2007 9:24 pm
Thanked: 2 times
Followed by:1 members

pt question

by jamesk486 » Mon May 07, 2007 6:53 am
Machine A working alone can complete a job in 3 1/2 hours. Machine B working alone can do the same job in 4 2/3 hours. How long will it take both machines working together at their respective constant rates to complete the job?

A. 1 hour 10 min
B. 2 hr
C. 4 hr 5 min
D. 7 hr
E. 8 hr 10 min
Top
Source: — Problem Solving |
Legendary Member
Posts: 559
Joined: Tue Mar 27, 2007 1:29 am
Thanked: 5 times
Followed by:2 members

by Cybermusings » Mon May 07, 2007 8:37 am
Machine A working alone can complete a job in 3 1/2 hours. Machine B working alone can do the same job in 4 2/3 hours. How long will it take both machines working together at their respective constant rates to complete the job?

A. 1 hour 10 min
B. 2 hr
C. 4 hr 5 min
D. 7 hr
E. 8 hr 10 min

A --- 7/2 hrs
B --- 14/3 hrs

Together in 1 hr = 1/(7/2) + 1/(14/3) = 2/7 + 3/14 = (4+3)/14
= 7/14 or 1/2 work

Hence complete work in 2 hrs
Top
Post new topic Post Reply
• Page 1 of 1