Question

A and b can do a piece of work in 72 days b and c can do it in 120 days and a and c can do it in 90 days .when a,b and c work together how much work is finished by them in 3 days

Answer 1

A and B can do work =72days
1 day work=1/72 days


B and C can do work =120 days
1 day work=1/120 days

A and C can do work =90 days
1 day work=1/90 days

They do work together=1/72+1/120+1/90
5+3+4/360=12/360=1/30
1/30×3=3/30=1/10=10 days
They can finished work in 3 days=10 days


Hope this help you.