Question

A can do a piece of work in 12 days and b can do it in 10 days and a, b and c together in 5 days. c alone can do it in:

Answer 1

work done by A=1/12days
work done by B=1/10days
work done by all =1/5 days
so the answer is C=1/5- (1/12+1/10)
=12/60-11/60
=1/60
the answer is 60 days