Calvin works at a pizza place making pizzas. If he is working alone, he can make an average of 15 3/4 per hour. If he works with his friend Megan, he tends to get distracted, and his rate falls by 1/2 per hour. How many pizzas can Calvin make in a 8- hour shift with Megan? Explain the operations that will be needed to solve this problem, ans then solve it.