Question

A and B can do a piece of work in 12 days ; B and C in 15 days ; C and A in 20 days. In how many days will they finish it together and separately?

Answer with steps plssss...

Answer 1

Hi there!

(A + B)’ s 1 day’s work = 1/12

(B + C)’ s 1 day’s work = 1/15

(C + A)’ s 1 day’s work = 1/20

On adding,
2(A + B + C)’ s 1 day’s work = 1/12 + 1/15 + 1/20 = 5+4+3/60 = 12/60 = 1/5

∴ (A + B + C)’ s 1 day’s work = 1/10

A’ s 1 day’s work = 1/10 - 1/15 = 3-2/30 = 1/30

B' s 1 day's work = 1/10 - 1/20 = 2-1/20 = 1/20

C' s 1 day's work = 1/10 - 1/12 = 6-5/60 = 1/60

Hence,

'A' alone can complete the work in 30 Days.

'B' alone can complete the work in 20 Days.

'C' alone can complete the work in 60 Days.

Cheers!