a paty of 10 scouts set of with enough food to last 7 days.

Question

After 4 days 4 scouts leave the paty.how many more days will the food last for the scouts who remained?

Answer 1

10 scouts with 7 days of food means they have 10 * 7 = 70 scout-days of food.

After 4 days the 10 scouts will have consumed 4 * 10 = 40 scout-days of food.

With 70 - 40 = 30 scout-days of food left, the remaining 10 - 4 = 6 scouts will have enough food for 30 / 6 = 5 days.