The cost of renting a bus for a field trip was split evenly among 20 students. At the last minute, 10 more students joined the trip. The cost of renting the bus was then evenly redistributed among all of the students. The cost for each of the original 20 students decreased by 1.50. What was the total cost of renting the bus, in dollars?
Let C be the cost per student before the price reduction....then we have that
20C = (20 + 10) (C - 1.50) simplify
20C = 30 ( C - 1.50)
20C = 30C - 45 add 45 to both sides, subtract 20C from both sides
45 = 10C divide both sides by 10
4.5 = C = $4.50
So...the cost for the bus is
20 (4.5) =
$90