Stephen ordered 2 large pizzas, both cut into 12 slices. He ate 25% of the pizza. His friend Pete ate 50% of the remaining pizza. How many slices are left over? Let's be accurate as possible.
He ordered 2 pizzas, each cut into 12 slices so that's 2 * 12 = 24 slices. Stephen ate 25% of the pizza so he ate .25 * 24 = 6 slices. That leaves 24 - 6 = 18 slices. 18 slices are left and Pete eats 50% of 18 slices so he eats 18 * .50 = 9 slices. If there were 18 slices and Pete ate 9 slices then there are 18 - 9 = 9 slices left over.
The answer: 9.