16 Primary 4 pupils and 10 of Primary 5 pupils went on a school outing. The number of Primary 5 boys was 3 times the number of Primary 4 boys, and there were 12 more Primary 4 girls than Primary 5 girls. How many less Primary 5 girls than Primary 5 boys went on the school outing?
| Primary 4 |
Primary 5 |
| 16 |
10 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 12 |
3 u |
1 p |
Total number of pupils in Primary 4 = 1 u + 1 p + 12
1 u + 1 p + 12 = 16
1 u + 1 p = 16 - 12
1 u + 1 p = 4 --- (1)
Total number of pupils in Primary 5 = 3 u + 1 p
3 u + 1 p = 10 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 10 - 4
3 u - 1 u = 6
2 u = 6
1 u = 6 ÷ 2 = 3
Number of boys in Primary 5
= 3 u
= 3 x 3
= 9
Number of girls in Primary 5
= 1 p
= 10 - 3 u
= 10 - 9
= 1
Number of less girls than boys in Primary 5
= 9 - 1
= 8
Answer(s): 8
