Mr Sam 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
14 of a pizza and the boys finished all the pizzas given to them. Each girl ate
18 of a pizza and the girls had 7
12 pizzas left. How many pizzas did Mr Sam buy?
|
Girls (1) |
Boys (2) |
Before |
3 u |
1 u |
Change |
- 1 p |
- 2 p |
After |
60 |
0 |
14 =
28 Cutting the slices of pizzas into same size. Each pizza was cut into 8 slices. Every girl ate 1 slice of pizza and every boy ate 2 slices of pizza.
Number of slices that the girls had left
= 7
12 ÷
18 =
152 x 8
= 60
3 u - 1 p = 60 --- (1)
1 u - 2 p = 0
1 u = 2 p --- (2)
Make u the same.
(2)
x33 u = 6 p --- (3)
Substitute (3) into (1).
3 u - 1 p = 60
6 p - 1 p = 60
5 p = 60
1 p = 60 ÷ 5 = 12
Total number of slices of pizzas for girls
= 60 + 1 p
= 60 + 12
= 72
Total number of slices of pizzas for boys
= 72 ÷ 3
= 24
Total number of slices of pizzas for students
= 72 + 24
= 96
Total number of pizzas that Mr Sam bought
= 96 ÷ 8
= 12
Answer(s): 12