Question

A can complete a piece of work in 10 days, B in 15 days and C in 20 days, A and C worked together for two days and then A was replaced by B. ln how many days, altogether, work was completed ? 

(a) 12 days 

(b) 10 days 

(c) 6 days 

(d) 8 days

Answer 1

Correct option (d) 8 days

Explanation: 

A and C work for two days. They completed 

(6+3)×2 days = 18 units

work left : 60 – 18 = 42 units

Now A replaces by B (B+C) one day work 

= 4 + 3 (B+C) complete remaining work in 

Total days 6 + 2 = 8 days