The cost varies directly with the number of tickets purchased. it costs $145 for 10 people to attend a concert. a. what is the constant of proportionality (k)? b. write the direct variation equation. c. home much does it cost for 8 people? d. graph this situation. be sure to label each axis and give the graph a title.

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?