The cost of manufacturing toothbrushes is 0.4 cents per brush. The cost of manufacturing dental floss is 0.5 cents per roll. Assume that if toothbrushes are sold at x cents each and dental floss is sold at y 50000 70000 cents per roll, then the demand function is for toothbrushes and for xy xy dental floss. What are the selling prices that correspond to maximum profit?