Question

Three friends are driving to New York City and splitting the gas cost equally. At the last minute, 2 more friends joined the trip. The cost of gas was then evenly redistributed among all of the friends. The cost for each of the original 3 decreased by $11.00. What was the total cost of the gas, in dollars?

Answer 1

Let x = the total cost of gas, dollars.

Originally, each of the three friends was to pay x/3 dollars each.
Finally, with two more friends added, the cost became x/5 dollars each.

The savings for each of the original three friends is $11, therefore
x/3 - x/5 = 11
(2x)/15 = 11
x = (11*15)/2 = $82.50

Answer: The total cost of gas is $82.50