25 Primary 4 pupils and 19 of Primary 5 pupils went on a school learning journey. The number of Primary 5 boys was 3 times the number of Primary 4 boys, and there were 16 more Primary 4 girls than Primary 5 girls. How many less Primary 5 girls than Primary 5 boys went on the school learning journey?
| Primary 4 |
Primary 5 |
| 25 |
19 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 16 |
3 u |
1 p |
Total number of pupils in Primary 4 = 1 u + 1 p + 16
1 u + 1 p + 16 = 25
1 u + 1 p = 25 - 16
1 u + 1 p = 9 --- (1)
Total number of pupils in Primary 5 = 3 u + 1 p
3 u + 1 p = 19 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 19 - 9
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of boys in Primary 5
= 3 u
= 3 x 5
= 15
Number of girls in Primary 5
= 1 p
= 19 - 3 u
= 19 - 15
= 4
Number of less girls than boys in Primary 5
= 15 - 4
= 11
Answer(s): 11
