Question

A and b can do a piece of work in 30 days while b and c can do the same work in 24 days and c and a in 20 days. If they all work together, in how many days will the work finish?

Answer 1

16 days.

Explanation:

The work done by a and b in one day = 1/30

The work done by b and c in one day = 1/24

The work done by c and a in one day = 1/20

Find the sum of all these fractions , this will be the work done by 2a and 2b and 2c in one day. This gives 0.125, which is equivalent to 1/8.

The work done by 2 of each person = 8, so it takes double this value for just one of each person, this is 16 days.

Hope this helps