The ratio of the boys to the girls in a kindergarten was 5 : 3. After 14 boys went home and 21 new girls came, there were 9 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 |
3 u |
3 u |
| Change |
- 14 |
+ 21 |
+ 21 + 9 = + 30 |
| After |
5 u |
3 u + 21 |
3 u + 30 |
Comparing boys and
girls in the end |
9 more |
|
|
Since the number of boys is 9 more than the number of girls in the end, when we
add 9 to (2) to form (3), the number of boys and girls in the end will be the same.
(1) = (3)
5 u - 14 = 3 u + 30
5 u - 3 u = 30 + 14
2 u = 44
1 u = 44 ÷ 2 = 22
Number of pupils in the end
= 5 u + 3 u - 14 + 21
= 8 u + 7
= 8 x 22 + 7
= 176 + 7
= 183
Answer(s): 183
