24 Primary 5 pupils and 15 of Primary 6 pupils went on a school trip. The number of Primary 6 girls was 4 times the number of Primary 5 girls, and there were 15 more Primary 5 boys than Primary 6 boys. How many more Primary 6 girls than Primary 6 boys went on the school trip?
| Primary 5 |
Primary 6 |
| 24 |
15 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 15 |
4 u |
1 p |
Total number of pupils in Primary 5 = 1 u + 1 p + 15
1 u + 1 p + 15 = 24
1 u + 1 p = 24 - 15
1 u + 1 p = 9 --- (1)
Total number of pupils in Primary 6 = 4 u + 1 p
4 u + 1 p = 15 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 15 - 9
4 u - 1 u = 6
3 u = 6
1 u = 6 ÷ 3 = 2
Number of girls in Primary 6
= 4 u
= 4 x 2
= 8
Number of boys in Primary 6
= 1 p
= 15 - 4 u
= 15 - 8
= 7
Number of more girls than boys in Primary 6
= 8 - 7
= 1
Answer(s): 1
