27 Primary 1 students and 18 of Primary 2 students went on a school learning journey. The number of Primary 2 boys was 3 times the number of Primary 1 boys, and there were 19 less Primary 2 girls than Primary 1 girls. How many less Primary 2 girls than Primary 2 boys went on the school learning journey?
| Primary 1 |
Primary 2 |
| 27 |
18 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 19 |
3 u |
1 p |
Total number of students in Primary 1 = 1 u + 1 p + 19
1 u + 1 p + 19 = 27
1 u + 1 p = 27 - 19
1 u + 1 p = 8 --- (1)
Total number of students in Primary 2 = 3 u + 1 p
3 u + 1 p = 18 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 18 - 8
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of boys in Primary 2
= 3 u
= 3 x 5
= 15
Number of girls in Primary 2
= 1 p
= 18 - 3 u
= 18 - 15
= 3
Number of less girls than boys in Primary 2
= 15 - 3
= 12
Answer(s): 12
