Question
P can do ½ of a work in 10 days and Q can do 1/5 of the
same work in 4 days. In how many days can both finish the work, working together?Solution
P can do ½ of a work in 10 days. So P can do the whole work in 10x2 = 20 days. Q can do 1/5 of the same work in 4 days. So Q can do the whole work in 4x5 = 20 days. Let's assume the total work is 20 units. Efficiency of P = 20/20 = 1 unit/day Efficiency of Q = 20/20 = 1 unit/day Time taken by both of them to finish the whole work when working together = 20/(1+1) = 20/2 = 10 days
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