We are given
The average income, I, in dollars is
(a)
now, we are given
average income is $275000
so,
now, we can set them equal
and then we can solve for x
we will have to use quadratic formula
we get
we need to find youngest age
It means that we need to choose smallest value
so,
............Answer
(b)
we are given
x=40
so, we can plug it and find I
..............Answer