21 Primary 2 students and 11 of Primary 3 students went on a school trip. The number of Primary 3 girls was 3 times the number of Primary 2 girls, and there were 14 more Primary 2 boys than Primary 3 boys. How many more Primary 3 girls than Primary 3 boys went on the school trip?
| Primary 2 |
Primary 3 |
| 21 |
11 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 14 |
3 u |
1 p |
Total number of students in Primary 2 = 1 u + 1 p + 14
1 u + 1 p + 14 = 21
1 u + 1 p = 21 - 14
1 u + 1 p = 7 --- (1)
Total number of students in Primary 3 = 3 u + 1 p
3 u + 1 p = 11 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 11 - 7
3 u - 1 u = 4
2 u = 4
1 u = 4 ÷ 2 = 2
Number of girls in Primary 3
= 3 u
= 3 x 2
= 6
Number of boys in Primary 3
= 1 p
= 11 - 3 u
= 11 - 6
= 5
Number of more girls than boys in Primary 3
= 6 - 5
= 1
Answer(s): 1
