Mr Simon bought some pizzas for a group of students. There was an equal number of girls and boys. The girls received 3 times as many pizzas as the boys. Each boy ate
16 of a pizza and the boys finished all the pizzas given to them. Each girl ate
118 of a pizza and the girls had 13
13 pizzas left. How many pizzas did Mr Simon buy?
|
Girls (1) |
Boys (2) |
Before |
3 u |
1 u |
Change |
- 1 p |
- 3 p |
After |
240 |
0 |
16 =
318 Cutting the slices of pizzas into same size. Each pizza was cut into 18 slices. Every girl ate 1 slice of pizza and every boy ate 3 slices of pizza.
Number of slices that the girls had left
= 13
13 ÷
118 =
403 x 18
= 240
3 u - 1 p = 240 --- (1)
1 u - 3 p = 0
1 u = 3 p --- (2)
Make u the same.
(2)
x33 u = 9 p --- (3)
Substitute (3) into (1).
3 u - 1 p = 240
9 p - 1 p = 240
8 p = 240
1 p = 240 ÷ 8 = 30
Total number of slices of pizzas for girls
= 240 + 1 p
= 240 + 30
= 270
Total number of slices of pizzas for boys
= 270 ÷ 3
= 90
Total number of slices of pizzas for students
= 270 + 90
= 360
Total number of pizzas that Mr Simon bought
= 360 ÷ 18
= 20
Answer(s): 20