The ratio of the girls to the boys in a kindergarten was 8 : 3. After 17 girls went home and 21 new boys came, there were 7 more girls than boys in the end. Find the number of children in the kindergarten in the end.
| |
Girls
(1) |
Boys
(2) |
(3) |
| Before |
8 u |
3 u |
3 u |
| Change |
- 17 |
+ 21 |
+ 21 + 7 = + 28 |
| After |
8 u |
3 u + 21 |
3 u + 28 |
Comparing girls and
boys in the end |
7 more |
|
|
Since the number of girls is 7 more than the number of boys in the end, when we
add 7 to (2) to form (3), the number of girls and boys in the end will be the same.
(1) = (3)
8 u - 17 = 3 u + 28
8 u - 3 u = 28 + 17
5 u = 45
1 u = 45 ÷ 5 = 9
Number of children in the end
= 8 u + 3 u - 17 + 21
= 11 u + 4
= 11 x 9 + 4
= 99 + 4
= 103
Answer(s): 103
