20 men can finish a work in 30 days. After how many days should 5 men leave the work so that the work may be finished in 35 days ?

20 men can finish a work in 30 days. After how many days should 5 men leave the work so that the work may be finished in 35 days ?

A 5

B 10

C 15

D none

Solution

Correct Answer: Option C

Let, After x days 5 men should leave

so, 20x + 15(35-x) = 20 × 30
or, 20x + 525 - 15x = 600
or, 5x = 75,
or, x = 15