Answer each question completely. Write the ratio in colon form and reduce to lowest term if necessary.

1. In a school, there are 21 teachers and 360 pupils. What is the ratio of teachers to pupils?
2. In a class, there are 24 girls and 26 boys. What is the ratio of teachers to pupils?
3. Allain is 160 cm tall and Rica is 130 cm tall. What is the ratio of Allan's height to Rica's?