An investor invests $10 000 at x% p. a . compound interest for 2 years. He finds that he receives $20 more in interest than if he had invested it at a simple interest rate of x % p. a . Find x .

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.