Engineering Homework Help

I’m working on a civil engineering question and need an explanation and answer to help me learn.

Discussion Question:
Your goal is to have $1,000,000 in 20 years in an investment account that is available for you to withdraw starting
21st year. To that end, you are evaluating multiple options. Which option would you prefer and why? For this
problem, assume that you have required cash on hand at the present time for investment.

Option #1: Put aside lump sum today, at 8% interest compounded annually.

Option #2: Invest a specific amount over time (over the next 18 years) at 10% compounded annually.

Option #3: Put aside a lump sum today, at 8% interest compounded annually for 10 years, at which point the account
balance in the 10th year reinvests in another account over next 10 years (specific amount for this account is
withdrawn and reinvested in another account every year) at 10% interest compounded annually. The first account
stops earning interest at the end of 10th year.
Hint: All cash flows must be brought at the same point for a true comparison. Also remember, a dollar today is
worth more than a dollar tomorrow.