Question

Raman completes 50% of a wk in 10 days. Mohan then joins Raman on the 11th day and they together complete the remaining wk in 2 days.How long will take if the entire wk is entrusted to Mohan alone ?

Answer 1

so, Raman can do the whole job in 20 days. That means

1/20+1/m=(1/2)/2 = 1/4
m+20=5m
m=5

Mohan can do the whole job in 5 days.

check: Raman does 1/2 the job
In each of the remaining days, he does 1/20 and Mohan does 1/5

So, 2(1/20+1/5) = 2(1/4) = 1/2
Then the whole job is done.