How do i solve this, i can't figure it out and it's my home work

Yo y do yall have 2 stars that means yall wrong bro

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 volume of a box varies directly with its length if a box in the group has a length of 30inches and k=24 what is its volume