You and your significant other disagree on investing philosophies. To not pick sides, you want to figure out what portfolio would work for each of you.

YOU: You are comfortable with a portfolio that has at most a standard deviation of 25%, you want to figure out what weights of the assets A, B, and C will give you the maximum return.

YOUR PARTNER: Your partner has figured out if they can hit an 18% return with their portfolio, they can retire at 55. In this case, what weights of the assets give the minimum standard deviation of the portfolio?

Hint: Manually try out different weights on the portfolio assets.

Bigger hint: Both answers end up with 0% weight in one of the assets!