Question

95. A and B can separately do a piece of work in 20
and 15 days respectively. They worked together
for 6 days, after which B was replaced by C. If the
work was finished in next 4 days, then the number
of days in which Calone could do the work will be​

Answer 1

Work done of A in one day = 1/20

Work done of B in one day=1/15

6 day of work of both And B =42/60

Remaining work =1-42/60= 18/60

4 day of work of A and C =

4/20+4/C = 18/60

=4/C =6/10 , C =40 days.

Hence C can do that work in 40days