The ratio of the boys to the girls in a kindergarten was 7 : 4. After 21 boys went home and 25 new girls came, there were 14 more boys than girls in the end. Find the number of children in the kindergarten in the end.
| |
Boys
(1) |
Girls
(2) |
(3) |
| Before |
7 u |
4 u |
4 u |
| Change |
- 21 |
+ 25 |
+ 25 + 14 = + 39 |
| After |
7 u |
4 u + 25 |
4 u + 39 |
Comparing boys and
girls in the end |
14 more |
|
|
Since the number of boys is 14 more than the number of girls in the end, when we
add 14 to (2) to form (3), the number of boys and girls in the end will be the same.
(1) = (3)
7 u - 21 = 4 u + 39
7 u - 4 u = 39 + 21
3 u = 60
1 u = 60 ÷ 3 = 20
Number of children in the end
= 7 u + 4 u - 21 + 25
= 11 u + 4
= 11 x 20 + 4
= 220 + 4
= 224
Answer(s): 224
