Answer
a. $1.63n+38.73$
b. $81.11$ dollars.
Work Step by Step
a. Based on the given conditions, we have
$a_1=40.36, d=1.63$
We have
$a_n=a_1+(n-1)d=40.36+1.63(n-1)=1.63n+38.73$
(in dollars, for rock concerts $n$ years after 1994)
b. For year 2020, we have
$n=2020-1994=26$
and
$a_{26}=1.63(26)+38.73=81.11$ dollars.
