Question

a and b can do a peace of work in 13days but b and c can do peace of in 26 days then when a and c collet do work then both complete work in how many days ​

Answer 1

According to the question, A and B take 18 days. So:

1/A + 1/B=1/18

and

1/B + 1/C=1/24 and

1/A + 1/C=1/30

Adding them all together, you get:

2/A + 2/B + 2/C=1/18 + 1/24 + 1/30=20+15+12/360=47/360

1/A + 1/B + 1/C=47/720

1 / 47/720=720/47 days