28 Primary 2 students and 22 of Primary 3 students went on a school trip. The number of Primary 3 boys was 3 times the number of Primary 2 boys, and there were 16 more Primary 2 girls than Primary 3 girls. How many less Primary 3 girls than Primary 3 boys went on the school trip?
| Primary 2 |
Primary 3 |
| 28 |
22 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 16 |
3 u |
1 p |
Total number of students in Primary 2 = 1 u + 1 p + 16
1 u + 1 p + 16 = 28
1 u + 1 p = 28 - 16
1 u + 1 p = 12 --- (1)
Total number of students in Primary 3 = 3 u + 1 p
3 u + 1 p = 22 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 22 - 12
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of boys in Primary 3
= 3 u
= 3 x 5
= 15
Number of girls in Primary 3
= 1 p
= 22 - 3 u
= 22 - 15
= 7
Number of less girls than boys in Primary 3
= 15 - 7
= 8
Answer(s): 8
