+ Problem #7
Katy received a gift card for $100 toward her mobile phone plan. If her plan charges $0.75 per minute
for phone calls, write an equation R(m) that expresses how much money will remain on her card after
m minutes of phone calls.

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?