Question

A and B can together finish a piece of work in 30 days. They worked at it for 20 days and then B left. The remaining work was done by A alone in 20 more days. A alone can finish the work in: 

(a) 60 days 

(b) 54 days 

(c) 48 days 

(d) 50 days

Answer 1

Correct option (a) 60 days

Explanation: 

(A+B) worked for 20 days so, they completed 

20×2 = 40 units

Work left : 60-40 = 20 units

A’s efficiency 1 units/day

A will complete the whole work in =