Query Detail : RBI Grade B Phase I

P can complete a piece of work in 10 days and Q in 15 days. P worked alone for 2 days and then Q completed the remaining work along with R in 9 days. In how many days can R working alone complete the work?
Garima,   October 18th 2019,  
RBI Grade B Phase I


Let total work = LCM of 10 & 15 = 30 units

So P''s 1 day work - 3 units & Q's 1 day work - 2 units

Now P's 2 day work = 3*2 = 6 units

So remaining work = 30 - 6 = 24 units

which is to be done by Q & R in 9 days so 1 day work of Q & R together = 24/9 = 8/3 units

So 1 day work of R = 8/3 - 2 = 2/3 units

So R can do whole job alone in = 30/(2/3) = 45 days