Question

10 men or 18 boys can do a piece of work in 15 days then 25 men and 15 boys together will do twice the work in ?

Answer 1

10 men= 18 boy
25 men= 18×25/ 10= 45 boy

now total no. of boy = 45+15= 60 boy

18 boy complete the work in 15 days
1 boy ---------------------–----------15×18---
60 -----------------------------------15×18/60=9/2 days

again 1 work = 9/2 hr
2 work= 9/2 ×2= 9 hr