31 Primary 4 students and 28 of Primary 5 students went on a school trip. The number of Primary 5 girls was 4 times the number of Primary 4 girls, and there were 15 more Primary 4 boys than Primary 5 boys. How many more Primary 5 girls than Primary 5 boys went on the school trip?
| Primary 4 |
Primary 5 |
| 31 |
28 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 15 |
4 u |
1 p |
Total number of students in Primary 4 = 1 u + 1 p + 15
1 u + 1 p + 15 = 31
1 u + 1 p = 31 - 15
1 u + 1 p = 16 --- (1)
Total number of students in Primary 5 = 4 u + 1 p
4 u + 1 p = 28 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 28 - 16
4 u - 1 u = 12
3 u = 12
1 u = 12 ÷ 3 = 4
Number of girls in Primary 5
= 4 u
= 4 x 4
= 16
Number of boys in Primary 5
= 1 p
= 28 - 4 u
= 28 - 16
= 12
Number of more girls than boys in Primary 5
= 16 - 12
= 4
Answer(s): 4
