A deli sells 960 sandwiches per day at a price of eight dollars each. Market survey shows that for every $.10 reduction in the price, 20 more sandwiches will be sold. How much does a deli charge in order to maximize revenue? A different market survey shows that for every $.20 reduction in the original eight dollar price, five more sandwiches will be sold. No how much does a deli charge in order to maximize revenue?

Data from 2005 for various age groups show that for each $100 increase in the median weekly income for whites, the median weekly income of blacks increases by $105. also, for workers of ages 25 to 54 the median weekly income for whites was $676 and for blacks was $527. (a) let w represent the median weekly income for whites and b the median weekly income for blacks, and write the equation of the line that gives b as a linear function of w. b = (b) when the median weekly income for whites is $760, what does the equation in (a) predict for the median weekly income for blacks?