13 Primary 2 students and 10 of Primary 3 students went on a school oversea trip. The number of Primary 3 boys was 3 times the number of Primary 2 boys, and there were 9 more Primary 2 girls than Primary 3 girls. How many more Primary 3 boys than Primary 3 girls went on the school oversea trip?
| Primary 2 |
Primary 3 |
| 13 |
10 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 9 |
3 u |
1 p |
Total number of students in Primary 2 = 1 u + 1 p + 9
1 u + 1 p + 9 = 13
1 u + 1 p = 13 - 9
1 u + 1 p = 4 --- (1)
Total number of students in Primary 3 = 3 u + 1 p
3 u + 1 p = 10 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 10 - 4
3 u - 1 u = 6
2 u = 6
1 u = 6 ÷ 2 = 3
Number of boys in Primary 3
= 3 u
= 3 x 3
= 9
Number of girls in Primary 3
= 1 p
= 10 - 3 u
= 10 - 9
= 1
Number of more boys than girls in Primary 3
= 9 - 1
= 8
Answer(s): 8
