But the U.S. middle
class has been shrinking steadily from 61% of all adults in 1971
(t = 0)
to 51% in 2011 (t = 4),
where t is measured in decades. Research has shown that this decline is approximately linear.â€
(a) Find a linear function f(t) giving the percentage of middle-income adults in decade t, where
t = 0
corresponds to 1971.
f(t) =
(b) If this trend continues, what will the percentage of middle-income adults be in 2041?
%
