Question

36 men can do a piece of work in 12 days in how many days 9 men can do the same work

Answer 1

This case seems to be in indirect proportion.
Less men, more days.

So, If we keep the values accordingly and let the days taken by 9 men be x. We get-

9 : 36 : 12 : x     (9men : 36 men : 12 days : x days)

→ (36 * 12) ÷ 9
→ 4 * 12 = 48 days

Answer- 9 men can do the same work in 48 days. 

I hope this is clear to you..!! :)