arithmetic - an orphanage had provision of food for 300 boys for 90 days after 20 days 50 boys left the orphanage the number of days for which remaining food will last is - skillgun

Solution: After 20 days : 300 boys had food for 70 days.
Suppose 250 boys had food for x days. Now, less boys, more days (Indirect proportion)
.'. 250 : 300 : : 70 : x
=> 250*x = 300*70
=> x = 300*70/250 = 84.