Question

A man is twice as fast as a woman and a woman is twice as fast as a boy in doing a work. If all of the, a man, a woman and a boy can finish the work in 7 days, A boy will do it alone ? 

(a) 49 

(b) 7 

(c) 6 

(d) 42

Answer 1

Correct option (a) 49

Explanation: 

Man Woman boy efficiency 4 : 2 : 1 total work 

= Time × (Efficiency of man+woman+boy) 

⇒7days × (4+2+1) = 49 units

Boy can do this work in = 49/1 = 49 days