Question
P and Q together finish a
piece of work in 12 days. R works at half the efficiency of P. Q alone can finish the work in 30 days. Now if Q and R work together to complete 2/3 of the job, and R is working at twice his usual efficiency, find how many days they will take.Solution
ATQ, P’s one day’s work = 1/12-1/30 = (5-2)/60 = 3/60 = 20 days So, P complete the work in 20 days. Let, total work is 120. Efficiency of P and Q is 6 and 4 respectively. R’s efficiency is = 6/2 = 3 So, required time is = [(120×(2/3))/(6+4)] = 8 days.
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