Using an exponential function, it is found that:
a) The doubling time of the salary is of approximately 20 years.
b) The salary will be of $160,000.
<h3>What is an exponential function?</h3>
An increasing exponential function is modeled by:

In which:
- A(0) is the initial value.
- r is the growth rate, as a decimal.
The growth rate for this problem is:
r = 0.035.
The doubling time is t for which A(t) = 2A(0), hence:






t = 20 years.
You retire in 40 years, which is 2 doubling periods, hence the salary will be of:
40000 x 2 x 2 = $160,000.
More can be learned about exponential functions at brainly.com/question/25537936
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