Here are a few examples to hopefully get you started
1. a) boys to girls in your class → 10 to 12
b) [tex] \frac{miles}{hour} [/tex] → [tex] \frac{80 miles}{2 hours} = \frac{40 miles}{1 hour} [/tex]
c) students to teachers in your school → 450 students: 15 teachers = 30 students: 1 teacher
