Problem 7: The time taken by an average swimmer to swim 100 meters, free style, at age x years is given by t(x) = 0.181x? - 8.463x + 147.376 seconds. Calculate the age at which it takes the swimmer the least amount of time to swim that distance. a) 23.4 years b) 48.5 years c) 23.1 years d) 23.7 years e) none of the above Problem 8: The shortest time the swimmer from the previous problem takes to swim that distance is: a) 23.4 years b) 28.5 years c) 23.4 seconds d) 48.5 seconds e) none of the above