GRE Algebra question 1. A group can charter a particular aircraft at a fixed total cost. If 36 people charter the aircraft rather than 40 people, then the cost per person is greater by $12. (a) What is the fixed total cost to charter the aircraft? (b) What is the cost per person if 40 people charter the aircraft? ans: 15. (a) $\$$4,320 (b) $\$$108 Can the answers be found with the information provided in the question? If yes , how? As far as I understand the question, my approach to the question is as follows: for 40 people, cost per person be x for 36 people, cost per person is x+12 so for 40 people, total cost is 40x for 36 people, total cost is 36(x+12)

Put $\,x=\,$ the fixed cost, then we're said, _exactly_ as you wrote down:

$$40x=36(x+12)\Longrightarrow 4x=36\cdot 12\Longrightarrow\;\; (b)\;\;x=108$$

With this you can do the rest.