Question

A can do a piece of work in 30 days. He works at it for 6 days and then B finishes it in 18 days. In what time can A and B together it ?

Answer 1

Thanks for A2A.

Now, A can do a piece of work in 80 days. So, let the TOTAL WORK = 80 units.

A -> 80 days = 1 unit/day

So, in 10 days, A has completed 10 units.

Remaining Work = 70 units.

Now, B finishes this in 42 days. So rate of work if B =70427042 =5353unit/day

Thus, A + B =1+531+53 = 8383

So, TIME TAKEN = 80838083 = 30 Days (Answer)

Answer 2

A's per day work= 1/30 B complete remaining work in 20 days,


work done by a in days=(1/30)6=1/5remaining

work= 5/6 done by B in 20 days then B's per day work=(5/6)(1/18)=1/24

work will completed both A & B working together is inverse of (1/30)+(1/24)=40/3