37 Primary 5 students and 33 of Primary 6 students went on a school learning journey. The number of Primary 6 boys was 3 times the number of Primary 5 boys, and there were 16 less Primary 6 girls than Primary 5 girls. How many less Primary 6 girls than Primary 6 boys went on the school learning journey?

Primary 5		Primary 6
37		33
Boys	Girls	Boys	Girls
1 u	1 p + 16	3  u	1 p

Total number of students in Primary 5 = 1 u + 1 p + 16

1 u + 1 p + 16 = 37
1 u + 1 p = 37 - 16
1 u + 1 p = 21 --- (1)

Total number of students in Primary 6 = 3 u + 1 p

3 u + 1 p = 33 --- (2)

(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 33 - 21
3 u - 1 u = 12
2 u = 12

1 u = 12 ÷ 2 = 6

Number of boys in Primary 6
= 3 u
= 3 x 6
= 18

Number of girls in Primary 6
= 1 p
= 33 - 3 u
= 33 - 18
= 15

Number of less girls than boys in Primary 6
= 18 - 15
= 3

Answer(s): 3