You’re 20 years old, and you’re trying to decide which career path to take based on the future expected streams of income. Occupation A has you earning $15,000 for 5 years, then $25,000 for then next 30 years. Occupation B has you earning only $1000 for 4 years, then $10,000 for 6 years, and finally $50,000 for the next 25 years. You plan to retire when you are 55.
a. Write out a formula to calculate the present value of each of these income streams, assuming the interest rate is r. [Hint: you don’t have to write out all 35 terms, you can use “...” when it is obvious what the next term is in a sequence.]
b. What occupation would be better if the interest rate was zero? If it was extremely high?