Answer:
7 pizzas.
Step-by-step explanation:
First you figure out how much the first three pizzas cost. 7x3 = 21. They paid $21 for the first 3. Subtract that number from the total cost.
45 - 21 = 24. Since the rest of the pizzas were only 6 dollars, divide the remaining amount by 6.
24/6 = 4. They bought 4 additional pieces. Add the amount of pizzas they bought together.
3 + 4 = 7
