Question

Maria is planning a party. Nancy, her friend, suggests that she

should order 3 pizzas for every 7 people. If she is expecting 21
people at the party, how many pizzas should she order?

Answer 1

9 pizzas

Explanation:

Maria is planning a party. She should order 3 pizzas for every 7 people. Let x be the number of pizzas Maria will order for 21 people, then

3 pizzas - 7 people

x pizzas - 21 people

Write a proportion:

`(3)/(x)=(7)/(21)`

Cross multiply:

`7\cdot x=21\cdot 3\\ \\7x=63\\ \\x=(63)/(7)=9\ pizzas`