Final answer:
To find how many pizzas Sandy bought, subtract the coupon amount from the total cost and divide by the cost of each pizza. Sandy bought 4 pizzas.
Step-by-step explanation:
To find out how many pizzas Sandy bought, we need to subtract the coupon amount from the total cost and divide it by the cost of each pizza. The total cost of the pizzas after applying the coupon is $35.50 - $5 = $30.50. Since each pizza costs $6.75, we can divide the total cost by the cost of each pizza to find the number of pizzas. $30.50 ÷ $6.75 = rac{30.50}{6.75} = 4.52.
However, we cannot have a fraction of a pizza, so we need to round the number down to the nearest whole number. Therefore, Sandy bought 4 pizzas.