The ratio of the boys to the girls in a kindergarten was 5 : 2. After 15 boys went home and 26 new girls came, there were 7 more boys than girls in the end. Find the number of pupils in the kindergarten in the end.
|
Boys (1) |
Girls (2) |
(3) |
Before |
5 u |
2 u |
2 u |
Change |
- 15 |
+ 26 |
+ 26 + 7 = + 33 |
After |
5 u |
2 u + 26 |
2 u + 33 |
Comparing boys and girls in the end |
7 more |
|
|
Since the number of boys is 7 more than the number of girls in the end, when we
add 7 to (2) to form (3), the number of boys and girls in the end will be the same.
(1) = (3)
5 u - 15 = 2 u + 33
5 u - 2 u = 33 + 15
3 u = 48
1 u = 48 ÷ 3 = 16
Number of pupils in the end
= 5 u + 2 u - 15 + 26
= 7 u + 11
= 7 x 16 + 11
= 112 + 11
= 123
Answer(s): 123