The sets of ordered pairs below represent the cost to fix a plumbing issue based on the number of hours. The first coordinate represents the hours and the second coordinate the cost. Select the sets of ordered pairs that are proportional relationships.
(2.100),(4,320)(400). (8,640)
(1.30), (3,170) (4,210), (6,290)
(1.135) 64210), (6,255),(6, 200))
2.150): (3,225), (7,525), (8,600)
(230) 6275), (6,330) (735))

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?