Previous Year Questions

Work done by P in a day = 1/5

Work done by Q in a day = 1/10

Work done by R in a day = 1/15

P + Q = 1/5 + 1/10 = 3/10

P + R = 1/5 + 1/15 = 4/15

Work done in three days = 3/10 + 4/15 + 3/10 = 26/30

Remaining work = 1- 26/30 = 4/30 = 2/15

Time taken by (P+R) to do the remaining work = (2/15) / (4/15) = ½ day

Total days = 3 + ½ = 7/2 days