The height at the top of a roller coaster hill is 10 times the height h feet of the starting point. The height decreases 100 feet from the top to the bottom of the hill. The height at the bottom of the hill is -10 feet.
Therefore, there is a zero elevation point between the starting point at h height and the bottom of the hill which is at - 10 feet from the zero elevation point.
Now, the elevation of the top of the hill from the zero elevation point is (100 - 10) = 90 feet.
