Question

A alone can do a piece of work in 12 days and B alone can do it in 15 days . What part of the work will they do in 3 days ?​

Answer 1

Step-by-step explanation:

A alone can do the work in 12 days he can do = 1/12 work in one day

B alone can do the work in 15 days. He can do = 1/15 work in one day

A works for 4 days Work ne=4*1/12=4/12=1/3 work remaining =1-1/3=2/3

A and B together can do=1/12+1/15= (5 + 4) / 60 = 9/60 work in 1 day.

To finish the remaining work together, they need =(2/3)/(9/60)=2/3*60/9= 40/9 days=4 4/9 days

They need 4 ,4/9 days to finish the work.

Answer 2

Solution

A's 1 day work =1/12

A's 4 day work =4/12

Remaining work =1−4/12=8/12=2/3

B's 1 day work =1/15

A and B can finish the work in =(12+15)×2/3

                                                   =27×2/3

                                                   =18

Hence A and B will together finish the work in 18 days