Question

Your teacher tells the class they can have a party but you have to plan it.There are 34 students in your class and you've all decided on personal-size pizza, either cheese orpepperoni. You collect $120 from the class but when you get to the pizza place, you forget how many ofeach kind of pizza you were supposed to order! Personal-size pepperoni pizzas cost $4 and personal-size cheese pizzas cost $3Find the number of each kind of pizza you must order

Answer 1

Let x be the number of pepperoni pizzas you must order and y be the number of cheese pizzas.

Then, we have the following system:

I) x + y = 34

II) 4x + 3y = 120

First, we multiply equation I by 3:

I) 3x + 3y = 102

II) 4x + 3y = 120

Now, we subtract equation I from equation II:

(4x - 3x) + (3y - 3y) = 120 - 102

x = 18

Then, y = 34 - 18 = 16

You must order 18 persona-size pepperoni pizzas and 16 personal-size cheese pizzas.