33 Primary 2 students and 24 of Primary 3 students went on a school trip. The number of Primary 3 girls was 3 times the number of Primary 2 girls, and there were 19 more Primary 2 boys than Primary 3 boys. How many less Primary 3 boys than Primary 3 girls went on the school trip?
Primary 2 |
Primary 3 |
33 |
24 |
Girls |
Boys |
Girls |
Boys |
1 u |
1 p + 19 |
3 u |
1 p |
Total number of students in Primary 2 = 1 u + 1 p + 19
1 u + 1 p + 19 = 33
1 u + 1 p = 33 - 19
1 u + 1 p = 14 --- (1)
Total number of students in Primary 3 = 3 u + 1 p
3 u + 1 p = 24 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 24 - 14
3 u - 1 u = 10
2 u = 10
1 u = 10 ÷ 2 = 5
Number of girls in Primary 3
= 3 u
= 3 x 5
= 15
Number of boys in Primary 3
= 1 p
= 24 - 3 u
= 24 - 15
= 9
Number of less boys than girls in Primary 3
= 15 - 9
= 6
Answer(s): 6