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

Redeem

work rates

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 142
Joined: Sat Feb 20, 2010 7:23 pm
Thanked: 8 times
Followed by:1 members

work rates

by bpgen » Sat Jun 19, 2010 7:45 am
Working independently, Susan can perform a certain task in 6 hr and Tom can perform it in 7 hr. If Susan and Tom work together at the task for 3 hr, at which point Susan leaves, how many hr will it take Tom to complete the task alone?

A-1/14
B-2/5
C-1/2
D-29/42
E-1
"Ambition is the path to success. Persistence is the vehicle you arrive in."
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 142
Joined: Sat Feb 20, 2010 7:23 pm
Thanked: 8 times
Followed by:1 members

by bpgen » Sat Jun 19, 2010 7:46 am
OA C
"Ambition is the path to success. Persistence is the vehicle you arrive in."
Top
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Sat Jun 19, 2010 8:36 am
susan perform 1/6 unit of work in 1 hr

tom perform 1/7 unit of work in 1 hr

for 1 hr they perform 13/42 unit of work

for 3 hr 13/14 unit of work

13/14+x(1/7)=1

(13+2x)/14=1

x=1/2
Top
User avatar
Legendary Member
Posts: 1309
Joined: Wed Mar 17, 2010 11:41 pm
Thanked: 33 times
Followed by:5 members

by pradeepkaushal9518 » Sat Jun 19, 2010 8:37 am
susan do in 6 hrs

in 1 hr she will do 1/6th of work

tom do in 7 hrs

in 1 hr he will do 1/7th

in 3 hrs susan will do 3/6=1/2 of work and tom will do 3/7 th of work so total work done in 3 hrs = 1/2+3/7=13/14

work left = 1-13/14=1/14

tom do 1/7 of job in 1 hr
so 1/14 he will do in 1/2 hrs
Top
Post new topic Post Reply
• Page 1 of 1