A thin tube stretched across a street counts the number of pairs of wheels that pass over it. A vehicle classified as type A with two axles registers two counts. A vehicle classified as type B with seven axles registers seven counts. During a 1-hour period, a traffic counter registered 79 counts. How many type A vehicles and type B vehicles passed over the traffic counter?

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?