How much should I pay?

We live in the Southern US. I have 3 boys (12, 10, and 9). Our neighbor’s daughter is 16. She would be in charge of them every Tuesday/Thursday from 8-1 (taking to swim lessons, to the library, the park, and other outings). I’m not really sure what I should be paying her an hour, any thoughts? She babysits for one of my friends two nights a week (her 6 year old son) and gets paid $30 a time (usually around 2 hours).