HELP I NEED HELP ASAP

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

The price of a car has been reduced from $19,000 to $11,590. what is the percentage decrease of the price of the car?

Iknow the answer but the calculator doesn't seem to give the right one