29 Primary 5 pupils and 22 of Primary 6 pupils went on a school oversea trip. The number of Primary 6 boys was 3 times the number of Primary 5 boys, and there were 15 less Primary 6 girls than Primary 5 girls. How many less Primary 6 girls than Primary 6 boys went on the school oversea trip?
| Primary 5 |
Primary 6 |
| 29 |
22 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 15 |
3 u |
1 p |
Total number of pupils in Primary 5 = 1 u + 1 p + 15
1 u + 1 p + 15 = 29
1 u + 1 p = 29 - 15
1 u + 1 p = 14 --- (1)
Total number of pupils in Primary 6 = 3 u + 1 p
3 u + 1 p = 22 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 22 - 14
3 u - 1 u = 8
2 u = 8
1 u = 8 ÷ 2 = 4
Number of boys in Primary 6
= 3 u
= 3 x 4
= 12
Number of girls in Primary 6
= 1 p
= 22 - 3 u
= 22 - 12
= 10
Number of less girls than boys in Primary 6
= 12 - 10
= 2
Answer(s): 2
