Question

If 5 men or 9 boys can do a piece of work in 15 days then 10 men 12 boys can finish the
same work in
(a) 4 1/2
(b) 9 days
(c) 18 days
(d) 36 days

Answer 1

This would be it
9 days.............

Answer 2

let the required number of days be X
5men=9boys
10men = 9/5*10=18 boys
10men and 12 boys = 18+12
= 30 boys
Now,
30:9:25:x
= 30*x = 9*25
=x= 9*25/30
=x= 15/2
=x=7.5 days