Question

A government transportation crew deposits 500 ft3
of salt into a salt dome each week to prepare for snowy weather for a small town. After 3 weeks the salt dome has 3000 ft3
of salt.

If it takes 10 more weeks for the salt dome to be filled, what is the capacity of the salt dome?

Answer 1

Each week adds 500 ft³. In 3 weeks they've added 3·500 = 1500 ft³, so initial amount was 3000 − 1500 = 1500 ft³. Ten more weeks adds 10·500 = 5000 ft³, so capacity = 3000 + 5000 = 8000 ft³.