32 Primary 3 students and 26 of Primary 4 students went on a school excursion. The number of Primary 4 boys was 3 times the number of Primary 3 boys, and there were 20 more Primary 3 girls than Primary 4 girls. How many less Primary 4 girls than Primary 4 boys went on the school excursion?
| Primary 3 |
Primary 4 |
| 32 |
26 |
| Boys |
Girls |
Boys |
Girls |
| 1 u |
1 p + 20 |
3 u |
1 p |
Total number of students in Primary 3 = 1 u + 1 p + 20
1 u + 1 p + 20 = 32
1 u + 1 p = 32 - 20
1 u + 1 p = 12 --- (1)
Total number of students in Primary 4 = 3 u + 1 p
3 u + 1 p = 26 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 26 - 12
3 u - 1 u = 14
2 u = 14
1 u = 14 ÷ 2 = 7
Number of boys in Primary 4
= 3 u
= 3 x 7
= 21
Number of girls in Primary 4
= 1 p
= 26 - 3 u
= 26 - 21
= 5
Number of less girls than boys in Primary 4
= 21 - 5
= 16
Answer(s): 16
