Question

A camp has $20$ days ration for $40$ troops. If after $5$ days,$10$ troops arrive, then, for how many days will the ration be sufficient?

Answer 1

Number of troops to begin with 40 .. total rations available for 20 days.After 5 days., 25% of the rations would have been consumed.40 troops would consume the remaining rations (75%) in 15 days.Adding 10 additional troops, the number would increase to 50 and that means rations would be consumed faster.

40 troops = 15 days

50 troops = ? days

Since the number of days are inversely proportional to the number of troops., we can compute the number of days the pending rations (d) would last as

50 * d = 40 * 15

or

d = 40 * 15/50 or d = 12 days.