24 Primary 1 pupils and 19 of Primary 2 pupils went on a school oversea trip. The number of Primary 2 boys was 3 times the number of Primary 1 boys, and there were 15 more Primary 1 girls than Primary 2 girls. How many more Primary 2 boys than Primary 2 girls went on the school oversea trip?
| Primary 1 |
Primary 2 |
| 24 |
19 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 15 |
3 u |
1 p |
Total number of pupils in Primary 1 = 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 2 = 3 u + 1 p
3 u + 1 p = 19 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 19 - 9
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of boys in Primary 2
= 3 u
= 3 x 5
= 15
Number of girls in Primary 2
= 1 p
= 19 - 3 u
= 19 - 15
= 4
Number of more boys than girls in Primary 2
= 15 - 4
= 11
Answer(s): 11
