I have this problem that says:

The school Mrs Jonono's son goes to has a staffing ratio of 2:40 (Teachers to learners).

5.1 Write the ratio in it's simplest form ( $\displaystyle 1:20$ )

5.2 If there are $\displaystyle 1260$ learners in the school, how many teachers are there?

5.3 If the school employs $\displaystyle 7$ more teachers, what is the new teacher : pupil ratio?

I don't understand the last two.

Thanks.