Question

A garrison has a provision for a certain number of days. after 15 days, 1/4th of the men left and the remaining provision lasted for as long as before. how many days the remaining provision would have lasted before

Answer 1

M*d=md
M*15=md
D=md-15m/3m/4
D=m(d-15)/3m/4
D=d-15/3/4
3d=4d-60
4d-3d=60
D=60