37 Primary 1 pupils and 30 of Primary 2 pupils went on a school oversea trip. The number of Primary 2 girls was 3 times the number of Primary 1 girls, and there were 19 more Primary 1 boys than Primary 2 boys. How many more Primary 2 girls than Primary 2 boys went on the school oversea trip?
Primary 1 |
Primary 2 |
37 |
30 |
Girls |
Boys |
Girls |
Boys |
1 u |
1 p + 19 |
3 u |
1 p |
Total number of pupils in Primary 1 = 1 u + 1 p + 19
1 u + 1 p + 19 = 37
1 u + 1 p = 37 - 19
1 u + 1 p = 18 --- (1)
Total number of pupils in Primary 2 = 3 u + 1 p
3 u + 1 p = 30 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 30 - 18
3 u - 1 u = 12
2 u = 12
1 u = 12 ÷ 2 = 6
Number of girls in Primary 2
= 3 u
= 3 x 6
= 18
Number of boys in Primary 2
= 1 p
= 30 - 3 u
= 30 - 18
= 12
Number of more girls than boys in Primary 2
= 18 - 12
= 6
Answer(s): 6