Question

a and b can do a piece of work in 20 days. a alone can finish the work in 25 days. if they undertake a work and are paid for the whole work, what will be the share of a?

Answer 1

a+b a
time 20 25
eff. 5 4
total work=l.c.m of 20,25 =100
a share 100/5=20

Answer 2

A and B can do a piece of work in 20 days

⇒ 1 day = 1/20 of the work

A alone can do the work in 25 days

⇒ 1 day = 1/25 of the work

Find the amount of work B can do in a day:

1/20 - 1/25 = 1/100

Find their ratio:

Ratio of A : B = 1/25 : 1/100

Multiply both sides by 100:

Ratio of A : B = 4 : 1

Answer: A should get 4 shares for every 1 share that B gets.