Question

P and Q can do a piece of work in 45 and 40 days respectively. They began the work together but P leaves after some days and Q finished the remaining work in 23 days. Then Q has worked for:
A) 9
B) 21
C) 32
D) None of these

Answer 1

A does the job in 45 days = 1/45

B does the job in 40 days = 1/40

A & B together completes the job = ?

After A leaves, B completes the remaining job in 23 days.

i.e B's part of job in 23days = 23/40

Remaining part 17/40 is done by A & B together in x no.of days.

i.e (x/45) + (x/40) = 17/40

==> x = 9 days

Soln:

A leaves after 9 days