8 men can dig a pit in 20 days. If a man works half as much again a s a boy, then 4 men and 9 boys can dig a similar pit in:  Pick one.
A) 10 days
B) 12 days
C) 15 days
D) 16 days
E) 20 days

Rationale: explanation : 1 work done = 8 × 20 1 man = 3 / 2 boys 1 boy = 2 / 3 men then , 9 boys = 9 × 2 / 3 men = 6 men then , 4 men + 9 boys = 10 men then , 8 × 20 = 10 × ? days ? days = 8 × 20 / 10 = 16 days . answer : option d
Answer: D