Can someone help figure out these problems?

16.) A marathoner ran the 26.2 mile New York City Marathon in 2 hours, 12 minutes. Like all the other runners, he started from a standing position. During the last 5 meters, his leg cramped and he fell down mph. and had to roll across the finish line. Prove that at least twice, the marathoner was running at exactly 1I 17.) The order and transportation cost C of bottles of Pepsi" is approximated by the function: C(x) =10,000. _ x 1x x+3, where x is the order size of bottles of Pepsi in hundreds. According to Rolle's Theorem, the rate of change of cost must be zero for some order size in the interval [3,6). Find the order size. 18.) A car company introduces a new car for which the number of cars sold S is the function S(1) = 300| 5-- 9 where t is the time in months. + +2 a.) Find the average rate of cars sold over the first 12 months. b.) During what month does the average rate of cars sold equal the rate of change of car sales