In the following ordinary annuity, the interest is compounded with each payment, and the payment is made at the end of the compounding period.

You and your new spouse each bring home$1600 each month after taxes and other payroll deductions. By living frugally, you intend to live on just one paycheck and save the other in a mutual fund yielding 7.92% compounded monthly. How long will it take to have enough for a 20% down payment on a $165,000 condo in the city? (Round your answer to two decimal places.)