The biologist captures 20 fish out of a small lake behind his college. He fastens a maker onto each of these and throws them bsck in the lake. A week later he again catches 20 fish. Of these 20 fish 2 have markers on them. How many fish could Dr. Ji estimate are in the pond ?

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.