Question

A and B can do a piece of work in 3 days, B
and C in 4 days, C and A in 4 days. The time
taken by C alone to do it is :​

Answer 1

Work done by A and B in 1d= 1/3

Work done by B and C in 1d= 1/4

Work done by C and A in 1d=

1/4

Work done by 2(A,B and C) in 1d=1/3+1/4+1/4=10/11=5/6

Work done by A,B and C in 1d= (5/6)÷2=5/12

Work don by C alone in 1d= (Work done by A,B,C in 1d)-(Work done by B and C in 1d)

(5/12)-(1/3)=1/6

So,C alone takes 6 days to finish the work.