P and Q together can do a work in 6 days. If P alone can do it in 15 days. In how many days can Q alone do it?

2 Answers on this Question

1. (Q+R) 6 days work

   = 7×6=42 Units

   then in 3 days = total work = 18

   P Completes = 60−42=18 units .

   P’s eff. 183 = 6 units/day

   Q’s eff= 10−6=4 units/day

   R’s eff = 7−4=3 units/day

   P completes whole work in =606 = 10 days

   R completes whole work in =603= 20 days

   diff , is20−10=10 days

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2. Assume Q can do the work alone in Q days:

   work of a day by both P and Q =>
   (1/15) + (1/Q ) = 1/6
   solving this Q = 10.

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