The ratio of the boys to the girls in a kindergarten was 7 : 2. After 11 boys went home and 24 new girls came, there were 5 more boys than girls in the end. Find the number of students in the kindergarten in the end.
| |
Boys
(1) |
Girls
(2) |
(3) |
| Before |
7 u |
2 u |
2 u |
| Change |
- 11 |
+ 24 |
+ 24 + 5 = + 29 |
| After |
7 u |
2 u + 24 |
2 u + 29 |
Comparing boys and
girls in the end |
5 more |
|
|
Since the number of boys is 5 more than the number of girls in the end, when we
add 5 to (2) to form (3), the number of boys and girls in the end will be the same.
(1) = (3)
7 u - 11 = 2 u + 29
7 u - 2 u = 29 + 11
5 u = 40
1 u = 40 ÷ 5 = 8
Number of students in the end
= 7 u + 2 u - 11 + 24
= 9 u + 13
= 9 x 8 + 13
= 72 + 13
= 85
Answer(s): 85
