Question

A and B working together; can do a piece of work in 9/2 hours. B and C working together can do it in 3 hours. C and A working together can do it in 9/4 hours. All of them begin the work at the same time. Find how much time they will take to finish the piece of work. 

(a) 3 hours 

(b) 2 hours 

(c) 2.5 hours 

(d) 3.25 hours

Answer 1

Correct option (b) 2 hours

Explanation:

A +B +C = 9/2 units/hours

(A+B+C) will complete whole work in