Question

if 3men or 9 boys can finish a piece of work in 21 days.In how many days can 5 men and boys together do the same piece of work ?

Answer 1

If 3 men can do in 27days ,then 1 can do in 7 days and 5 into 7 is 35 days

Answer 2

Question -

If 3 men and 9 boys can finish a piece of work in 21 days. In how many days can 5 men and 6 boys together do the same piece of work ?

Answer : 9 Days

Explanation -

Given :

3 men can finish the work in 21 days.

9 boys can finish the work in 21 days.

3 men = 9 boys. So, 1 man = 3 boys.

Finding Number of working days by 1 man -

If 3 men can finish work in 21 days.

then 1 man can finish it in   ? =  21 x 3 = 63 days.

Finding Number of working days by 1 boy -

If 9 boys can finish the work in 21 days.

then 1 boy can finish it in  ? = 21 x 9 = 189 days.

Total number of boys -

If 1 man = 3 boys.

then 5 men = 5 x 3 = 15 boys.

15 boys + 6 boys = 21 boys.

Finding Number of working days by 5 men and 6 boys

5 men + 6 boys = 21 boys

1 boy can finish work in 189 days

21 boys can finish it = 189 ÷ 21 = 9 days.

Hence :

5 men and 6 boys can finish the work in 9 days.