The following table shows the average total cost, measured as dollars expended per pupil, of operating a high school with the given enrollment. This table is based on a study of economies of scale in high school operations from the 1960s.

Enrollment 170 250 450 650

Average total cost 538 473 429 413

What is the average growth rate of the average cost per additional student enrolled, when moving from an enrollment of 450 students to an enrollment of 650 students?

The average growth rate per students added is

_____cents

less or more expensive. I answered .41cents less expensive. That was incorrect. I took the enrolled of 450 divided by cost and did that for the 650 enrolled. Received:

1.04895105

-.63538462

.41 cents but that was not correct?