Your nephew, Caleb, is $25$ years old and has decided to start a retirement program. Beginning in exactly one month he will contribute the amount of $$1300$ every month into a retirement account. $80\%$ of the funds will be invested in a high$-$yield equity fund that is expected to earn $8\%$ annually; $20\%$ of the contribution will be invested in a lower$-$yield bond fund that is expected to return $5\%$ annually. He will continue to make contributions for the next $40$ consecutive years. When he retires, he will combine his money into an account with an annual return of $2\%.$ Assuming he lives another $25$ years, what is the maximum amount he will be able to withdrawal per month upon retirement?

Show me how I would set up this question and solve it in excel