35 Primary 1 pupils and 31 of Primary 2 pupils went on a school outing. The number of Primary 2 girls was 3 times the number of Primary 1 girls, and there were 16 less Primary 2 boys than Primary 1 boys. How many less Primary 2 boys than Primary 2 girls went on the school outing?
| Primary 1 |
Primary 2 |
| 35 |
31 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 16 |
3 u |
1 p |
Total number of pupils in Primary 1 = 1 u + 1 p + 16
1 u + 1 p + 16 = 35
1 u + 1 p = 35 - 16
1 u + 1 p = 19 --- (1)
Total number of pupils in Primary 2 = 3 u + 1 p
3 u + 1 p = 31 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 31 - 19
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
= 31 - 3 u
= 31 - 18
= 13
Number of less boys than girls in Primary 2
= 18 - 13
= 5
Answer(s): 5
