List Only

Help me with this math problem !!?

The high school students council has decided to have a dance a thon and needs to hire a disk jockey for the event. They have investegated 2 companies. Derek's DJ service charges $100 + $ 40 per hour. Solid sounds charges $ 175 plus $ 30 per hour. Wich is the most affordable option that they should selct?

Public Comments

1. The second service, if the dance a thon is 8 or more hours.
2. Well does it say how long they will be needing their service?