In a school hostel,there is enough food for 30 days. After 10 days, 40 students left the hostel and 100 more students join the hostel.how long will the food last?

Answer 1

After 10 days, there was enough food for 20 days for x students. So, if the number of students grew from x to x+60, it will only last

20x/(x+60) = 20 - 1200/x+60

more days. So, it depends on how many students there were to start with. If there were x at first, then the 20-day supply will be divided among x+60, as shown in the table below. The more students there were at first, the longer the remaining food will last the increased number of students.

x__n
40 800/100 = 8
41 820/101 = 8.1
60 1200/100 = 12
100 2000/160 = 12.5
1000 20000/1060 = 18.86

The longest the remaining food will last is 20 days, if there was a very large number to start with