Your subscription to BusinessWeek is about to expire. You plan to subscribe to the magazige for the rest of your life. You can renew it by paying $$50$ annually, beginning immediately, or you can get a lifetime subscription for $$500,$ also payable immediately. Assuming that you can earn $6\mathrm{.}525\%$ on your funds and that the annual renewal rate will remain constant, how many years must you live to make the lifetime subscription the better buy?

$15$

$12$

$10$

$18$