The number of boys to the number of girls in Primary 2 Love was 3 : 5. The number of boys to the number of girls in Primary 2 Goodness was 2 : 5. Both classes had the same number of boys. When 8 girls from Primary 2 Love joined Primary 2 Goodness, the ratio of the number of boys to the number of girls in Primary 2 Love became 3 : 4. Find the total enrolment of both classes.
| Primary 2 Love |
Primary 2 Goodness |
| Boys |
Girls |
Boys |
Girls |
| 3x2 |
5x2 |
2x3 |
5x3 |
| 1x6 |
|
1x6 |
|
| 6 u |
10 u |
6 u |
15 u |
The number of boys in both classes is the same. Make the number of boys the same. LCM of 3 and 2 is 6.
| |
Primary 2 Love |
Primary 2 Goodness |
| |
Boys |
Girls |
Boys |
Girls |
| Before |
6 u |
10 u |
6 u |
15 u |
| Change |
|
- 8 |
|
+ 8 |
| After |
3x2 =
6 u |
4x2 =
8 u |
6 u |
15 u + 8 |
The number of boys in Primary 2 Love remains unchanged. Make the number of boys in Primary 2 the same. LCM of 6 and 3 is 6.
Number of girls from Primary 2 Love that joined Primary 2 Goodness
= 10 u - 8 u
= 2 u
2 u = 8
1 u = 8 ÷ 2 = 4
Total enrolment of both classes
= 6 u + 10 u + 6 u + 15 u
= 37 u
= 37 x 4
= 148
Answer(s): 148
