40 Primary 1 pupils and 34 of Primary 2 pupils went on a school excursion. The number of Primary 2 girls was 3 times the number of Primary 1 girls, and there were 18 more Primary 1 boys than Primary 2 boys. How many less Primary 2 boys than Primary 2 girls went on the school excursion?
| Primary 1 |
Primary 2 |
| 40 |
34 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 18 |
3 u |
1 p |
Total number of pupils in Primary 1 = 1 u + 1 p + 18
1 u + 1 p + 18 = 40
1 u + 1 p = 40 - 18
1 u + 1 p = 22 --- (1)
Total number of pupils in Primary 2 = 3 u + 1 p
3 u + 1 p = 34 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 34 - 22
3 u - 1 u = 12
2 u = 12
1 u = 12 ÷ 2 = 6
Number of girls in Primary 2
= 3 u
= 3 x 6
= 18
Number of boys in Primary 2
= 1 p
= 34 - 3 u
= 34 - 18
= 16
Number of less boys than girls in Primary 2
= 18 - 16
= 2
Answer(s): 2
