Question

A and B can do a job together in 12 days. A is 2 times as efficieIlt as B. In how many days can B alone complete the work ? 

(a) 18 days 

(b) 9 days 

(c) 36 days 

(d) 12 days

Answer 1

Correct option (c) 36 days

Explanation: 

According to question, Efficiency A : B

2 : 1

If B does 1 unit of work A will do 2 units of work. So in a day,

they will complete 3 units of work together.

Total work = 12 days × 3 units/day = 36 units

B can complete the whole work alone in 

⇒ 36/1 = 36 days