At Citizen Bank Ball Park in Philadelphia, the "hot dog" man earns a certain amount of money to show up to work plus an additional amount of money for each hot dog he sells. On Friday evening, the hot dog man made $142.50 by selling 75 hot dogs. On Saturday evening, the hot dog man made $220.50 by selling 135 hot dogs.

1. How much money did the hot dog man make for each hot dog he sold?

2. how much money did he earn just showing up?

3. write an equation that gives the hot dog mans daily earning [y] as a function of the number of hotdogs he sells [x]

4. if on sunday the hotdog man made 184.10, how many hotdogs did he sell? ​