26 Primary 4 students and 20 of Primary 5 students went on a school trip. The number of Primary 5 boys was 3 times the number of Primary 4 boys, and there were 18 less Primary 5 girls than Primary 4 girls. How many less Primary 5 girls than Primary 5 boys went on the school trip?
| Primary 4 |
Primary 5 |
| 26 |
20 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 18 |
3 u |
1 p |
Total number of students in Primary 4 = 1 u + 1 p + 18
1 u + 1 p + 18 = 26
1 u + 1 p = 26 - 18
1 u + 1 p = 8 --- (1)
Total number of students in Primary 5 = 3 u + 1 p
3 u + 1 p = 20 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 20 - 8
3 u - 1 u = 12
2 u = 12
1 u = 12 ÷ 2 = 6
Number of boys in Primary 5
= 3 u
= 3 x 6
= 18
Number of girls in Primary 5
= 1 p
= 20 - 3 u
= 20 - 18
= 2
Number of less girls than boys in Primary 5
= 18 - 2
= 16
Answer(s): 16
