37 Primary 2 students and 29 of Primary 3 students went on a school oversea trip. The number of Primary 3 girls was 5 times the number of Primary 2 girls, and there were 20 less Primary 3 boys than Primary 2 boys. How many less Primary 3 boys than Primary 3 girls went on the school oversea trip?
Primary 2 |
Primary 3 |
37 |
29 |
Girls |
Boys |
Girls |
Boys |
1 u |
1 p + 20 |
5 u |
1 p |
Total number of students in Primary 2 = 1 u + 1 p + 20
1 u + 1 p + 20 = 37
1 u + 1 p = 37 - 20
1 u + 1 p = 17 --- (1)
Total number of students in Primary 3 = 5 u + 1 p
5 u + 1 p = 29 --- (2)
(2) - (1)
(5 u + 1 p) - (1 u + 1 p) = 29 - 17
5 u - 1 u = 12
4 u = 12
1 u = 12 ÷ 4 = 3
Number of girls in Primary 3
= 5 u
= 5 x 3
= 15
Number of boys in Primary 3
= 1 p
= 29 - 5 u
= 29 - 15
= 14
Number of less boys than girls in Primary 3
= 15 - 14
= 1
Answer(s): 1