If buying a smartphone for $607 and putting the entire balance on a credit card that charges 18% compounded semi annually, what would the credit card change. in an simplified expression? i’m confused and don’t know how to start it.

Which one ? is the answer and how to find this answer

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.

Aefg - almn. find the ratio of aefg to almn. a)1: 4 b)1: 2 c)2.1 d)4: 1