Mr Ahmad bought some pizzas for a group of pupils. There was an equal number of boys and girls. The boys received 4 times as many pizzas as the girls. Each girl ate ¹₅ of a pizza and the girls finished all the pizzas given to them. Each boy ate ¹₁₀ of a pizza and the boys had 5³₅ pizzas left. How many pizzas did Mr Ahmad buy?

	Boys (1)	Girls (2)
Before	4 u	1 u
Change	- 1 p	- 2 p
After	56	0

¹₅ = ²₁₀

Cutting the slices of pizzas into same size. Each pizza was cut into 10 slices. Every boy ate 1 slice of pizza and every girl ate 2 slices of pizza.

Number of slices that the boys had left
= 5³₅ ÷ ¹₁₀ 
= ²⁸₅ x 10
= 56

4 u - 1 p = 56 --- (1)

1 u - 2 p = 0
1 u = 2 p --- (2)

Make u the same.

(2)_x4
4 u = 8 p --- (3)

Substitute (3) into (1).
4 u - 1 p = 56
8 p - 1 p = 56
7 p = 56

1 p = 56 ÷ 7 = 8

Total number of slices of pizzas for boys
= 56 + 1 p
= 56 + 8
= 64

Total number of slices of pizzas for girls
= 64 ÷ 4
= 16

Total number of slices of pizzas for pupils
= 64 + 16
= 80

Total number of pizzas that Mr Ahmad bought
= 80 ÷ 10
= 8

Answer(s): 8