25 Primary 3 students and 21 of Primary 4 students went on a school excursion. The number of Primary 4 girls was 3 times the number of Primary 3 girls, and there were 14 more Primary 3 boys than Primary 4 boys. How many more Primary 4 girls than Primary 4 boys went on the school excursion?
| Primary 3 |
Primary 4 |
| 25 |
21 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 14 |
3 u |
1 p |
Total number of students in Primary 3 = 1 u + 1 p + 14
1 u + 1 p + 14 = 25
1 u + 1 p = 25 - 14
1 u + 1 p = 11 --- (1)
Total number of students in Primary 4 = 3 u + 1 p
3 u + 1 p = 21 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 21 - 11
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of girls in Primary 4
= 3 u
= 3 x 5
= 15
Number of boys in Primary 4
= 1 p
= 21 - 3 u
= 21 - 15
= 6
Number of more girls than boys in Primary 4
= 15 - 6
= 9
Answer(s): 9
