Question

Lena and 3 of her friends bought just enough food to go on a 12- day camping trip. Pete and Jane surprised them by showing up at the start of the trip and asking to join, but they brought no food. By what percent would the time for the trip shorten for the trip if everyone ate their normal portions?

Answer 1

The number of people increased by 2.

This means as a ratio it is now 6/4 as many as originally planned.

6/4 can be reduced to 3/2.

The time and the number of people are inversely proportional, so the food would last 2/3 ( inverse is flipping the original ratio over) the original length of time.

This means the length of time the food lasts is reduced by 1/3, which is 33.3%