32 Primary 2 pupils and 28 of Primary 3 pupils went on a school learning journey. The number of Primary 3 girls was 3 times the number of Primary 2 girls, and there were 18 less Primary 3 boys than Primary 2 boys. How many less Primary 3 boys than Primary 3 girls went on the school learning journey?
| Primary 2 |
Primary 3 |
| 32 |
28 |
| Girls |
Boys |
Girls |
Boys |
| 1 u |
1 p + 18 |
3 u |
1 p |
Total number of pupils in Primary 2 = 1 u + 1 p + 18
1 u + 1 p + 18 = 32
1 u + 1 p = 32 - 18
1 u + 1 p = 14 --- (1)
Total number of pupils in Primary 3 = 3 u + 1 p
3 u + 1 p = 28 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 28 - 14
3 u - 1 u = 14
2 u = 14
1 u = 14 ÷ 2 = 7
Number of girls in Primary 3
= 3 u
= 3 x 7
= 21
Number of boys in Primary 3
= 1 p
= 28 - 3 u
= 28 - 21
= 7
Number of less boys than girls in Primary 3
= 21 - 7
= 14
Answer(s): 14
