A garrison of 120 people had enough food for 30 days. If 20 people leave the garrison after 10 days, how long do the remaining provisions last?

We know that no. of days is inversely propotional to the provision for men.

So for 120 men the provision would last for 30days. (given)

Therefore, the provision for 1 men would sustain for. 120 *30 = 3600 days.

Let after the joining of 5 men (after 5 days) the no of more days the provision would last is x days

A.t.q 120*30 = 120*5+125*x

(120*30) - (120*5)= 125x

120(30-5)=125x

120 * 25 = 125x

120 = 5x

x=120/5

x= 24

so the provision would remain for more 24 days.

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.