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

Redeem

work/rate

Expert replies
Source: — Problem Solving |

Re: work/rate

by sudhir3127 » Mon Sep 01, 2008 9:31 am
superrrom wrote:Thanks
7000B= 100000- 9000*8

7000b = 28000

hence b takes 28000/7000 hr = 4

hope that helps..
Join the discussion

by II » Mon Sep 01, 2008 1:54 pm
I used similar approach as Sudhir here. Just to add some more explanation ...

Question is asking to us find out the least amount of time that Machine B needs to work. We know that the maximum working time is 8 hours ... so if Machine A worked for for its maximum time: 8 hours, then it would have produced 9000*8 = 72000 pencils.
This leaves 28000 pencils to be produced (100000-72000).
From this we can work out how long machine B needs to work.

RT = W
T = W/R
T = 28000/7000
T = 4
Join the discussion

by canuckclint » Wed Sep 03, 2008 2:11 pm
You want to maximize A's production and work it for 8 hours.

9000 * 8 will produce 72,000 pencils.
72,000 + 7000 * TimeB = 100,000
TimeB = 4 hours
Join the discussion