Final answer:
Ben needs to order 3 large pizzas to ensure everyone gets 2 slices of pizza.
Step-by-step explanation:
To determine how many large pizzas Ben needs to order, we can use basic division. Since there are 9 people and each person wants 2 slices, we need a total of 9 x 2 = 18 slices. Since a large pizza has 8 slices, we divide 18 by 8 to find the number of large pizzas needed.
18 ÷ 8 = 2.25
Ben would need to order 3 large pizzas to ensure that everyone gets 2 slices of pizza. However, since we can't order a fraction of a pizza, Ben needs to round up to the next whole number. Therefore, Ben should order 3 large pizzas.