26 Primary 5 pupils and 16 of Primary 6 pupils went on a school oversea trip. The number of Primary 6 girls was 3 times the number of Primary 5 girls, and there were 18 less Primary 6 boys than Primary 5 boys. How many less Primary 6 boys than Primary 6 girls went on the school oversea trip?
| Primary 5 |
Primary 6 |
| 26 |
16 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 18 |
3 u |
1 p |
Total number of pupils in Primary 5 = 1 u + 1 p + 18
1 u + 1 p + 18 = 26
1 u + 1 p = 26 - 18
1 u + 1 p = 8 --- (1)
Total number of pupils in Primary 6 = 3 u + 1 p
3 u + 1 p = 16 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 16 - 8
3 u - 1 u = 8
2 u = 8
1 u = 8 ÷ 2 = 4
Number of girls in Primary 6
= 3 u
= 3 x 4
= 12
Number of boys in Primary 6
= 1 p
= 16 - 3 u
= 16 - 12
= 4
Number of less boys than girls in Primary 6
= 12 - 4
= 8
Answer(s): 8
