28 Primary 5 students and 22 of Primary 6 students went on a school camp. The number of Primary 6 girls was 3 times the number of Primary 5 girls, and there were 20 more Primary 5 boys than Primary 6 boys. How many more Primary 6 girls than Primary 6 boys went on the school camp?
| Primary 5 |
Primary 6 |
| 28 |
22 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 20 |
3 u |
1 p |
Total number of students in Primary 5 = 1 u + 1 p + 20
1 u + 1 p + 20 = 28
1 u + 1 p = 28 - 20
1 u + 1 p = 8 --- (1)
Total number of students in Primary 6 = 3 u + 1 p
3 u + 1 p = 22 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 22 - 8
3 u - 1 u = 14
2 u = 14
1 u = 14 ÷ 2 = 7
Number of girls in Primary 6
= 3 u
= 3 x 7
= 21
Number of boys in Primary 6
= 1 p
= 22 - 3 u
= 22 - 21
= 1
Number of more girls than boys in Primary 6
= 21 - 1
= 20
Answer(s): 20
