25 Primary 1 students and 16 of Primary 2 students went on a school learning journey. The number of Primary 2 girls was 3 times the number of Primary 1 girls, and there were 15 less Primary 2 boys than Primary 1 boys. How many less Primary 2 boys than Primary 2 girls went on the school learning journey?
Primary 1 |
Primary 2 |
25 |
16 |
Girls |
Boys |
Girls |
Boys |
1 u |
1 p + 15 |
3 u |
1 p |
Total number of students in Primary 1 = 1 u + 1 p + 15
1 u + 1 p + 15 = 25
1 u + 1 p = 25 - 15
1 u + 1 p = 10 --- (1)
Total number of students in Primary 2 = 3 u + 1 p
3 u + 1 p = 16 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 16 - 10
3 u - 1 u = 6
2 u = 6
1 u = 6 ÷ 2 = 3
Number of girls in Primary 2
= 3 u
= 3 x 3
= 9
Number of boys in Primary 2
= 1 p
= 16 - 3 u
= 16 - 9
= 7
Number of less boys than girls in Primary 2
= 9 - 7
= 2
Answer(s): 2