Problema Solution
In 1980, median family income was about $18,000, and in 2000 it was about $42,000.
(a) find the slope of the line passing through the points (1980,18000) and (2000,42000).
(b) Interpret the slope as a change.
(c) If this trend continues, estimate the median family income in 2007
Answer provided by our tutors
a.Slope = (y2-y1)/(x2-x1) = (42000-18000)/(2000-1980) = 24000/20 = 1200
b. Slope being 1200 means that If x changes by 1 unit then y changes by 1200 units.
c. In 7 years it will increase by 1200*7=8400 than it was in the year 2000
So, in 2007 , median income = 8400 + 42000 = $50400 [ans]