Mrs Wong baked some pizzas for her students. The boy received twice as many pizzas as the girls. There were as many girls as boys in the class. Each girl ate 4/9 of a pizza and they finished all pizzas that were given to them. Each bot ate 3/4 of a pizza and they had 3 3/4 pizzas left.

A) how many girls were there?
B) how many pizzas did mrs wong bake?

2 answers

Let n = number of boys or girls
Let p = received pizza by girls
Let 2p = received pizza by boys

Each girl ate 4/9 of a pizza and they finished all pizzas that were given to them:
4/9 * n = p

Each boy ate 3/4 of a pizza and they had 3 3/4 pizzas left:
3/4 * n = 2p - 3 3/4

Substituting the first equation to the second:
3/4 * n = 2(4/9 * n) - 3 3/4
3/4 * n = 8/9 * n - 15/4
Multiply everything by 36.
27n = 32n - 135
-5n = -135
n = 27 girls or boys

Now solve for p by substituting n = 27 to either equation. Since the second question asks for the total pizza baked, you should solve for p + 2p.

Hope this helps~ :3
Thank you!