Theorem 1. If f is a continuous function on the closed interval [a, b] and differ- entiable on the open interval (a, b), then there exists a point c in the interval (a, b) such that f'(c) f(b)-f(a) = b-a Try to use it to solve the next problem. Problem 2. A car traverses a tunel which is 1km long in 50 seconds. If the speed limit inside the tunel is 60 km/h, can we guarantee that the car went over the speed limit?