A store owner buys up to 100 liters of milk from a wholesaler at the beginning of the day with the price per liter equal to 2 - (x/400) dollars, where x is the total amount (in liters) that he buys. He then sells it during the day at 3 dollar per liter. Any unsold milk is wasted. The daily demand (in liter) is random, uniformly distributed on the interval [0,100]. What amount of milk should the store-owner buy to maximize his expected profit