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# Work problem

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SVP
Joined: 28 Dec 2005
Posts: 1500

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18 Jun 2009, 04:00
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Q:- A can do some work in 12 hours, B can do the same work in 16 hours and C can do the same work in 30 hours. They start working together. A left after 3 hours and B left after working for 4 hours. How many more hours are required to complete the whole work after B has left?
(A)15
(B) 11
(C)12
(D) 9
(E) 10
Senior Manager
Joined: 08 Jan 2009
Posts: 317

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18 Jun 2009, 04:53
Ans . B

A = 1/12 B = 1/16 and C = 1/30

A +B + C 1 hr work = 1/12 + 1/16 + 1/30 = 43 / 240

Since they work together for 3 hours its 43 /240 * 3 = 129 /240

B + C 1 hr work = 1/16 + 1/30 = 23 / 240

So 129 /240 + 23 / 240 + x = 1 so x = 88/240

C take 30 days to do = 1 work

so C does 88/240 in = 88/240 * 30 = 11 hr
Re: Work problem   [#permalink] 18 Jun 2009, 04:53
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