16 Primary 3 pupils and 11 of Primary 4 pupils went on a school excursion. The number of Primary 4 girls was 3 times the number of Primary 3 girls, and there were 9 more Primary 3 boys than Primary 4 boys. How many less Primary 4 boys than Primary 4 girls went on the school excursion?
| Primary 3 |
Primary 4 |
| 16 |
11 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 9 |
3 u |
1 p |
Total number of pupils in Primary 3 = 1 u + 1 p + 9
1 u + 1 p + 9 = 16
1 u + 1 p = 16 - 9
1 u + 1 p = 7 --- (1)
Total number of pupils in Primary 4 = 3 u + 1 p
3 u + 1 p = 11 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 11 - 7
3 u - 1 u = 4
2 u = 4
1 u = 4 ÷ 2 = 2
Number of girls in Primary 4
= 3 u
= 3 x 2
= 6
Number of boys in Primary 4
= 1 p
= 11 - 3 u
= 11 - 6
= 5
Number of less boys than girls in Primary 4
= 6 - 5
= 1
Answer(s): 1
