Jack asked Jill to marry​ him, and she has accepted under one​ condition: Jack must buy her a new ​$320,000 ​Rolls-Royce Phantom. Jack currently has $10,260 that he may invest. He has found a mutual fund with an expected annual return of 8 percent in which he will place the money. How long will it take Jack to win​ Jill's hand in​ marriage? Ignore taxes and inflation.