A gambler has k dollars at the beginning of his day of gambling. He pays a $5 admission fee to enter the casino. When he leaves the casino he has twice as much money as he had when he started gambling. He then goes to another casino, and pays anothe $5 admission fee. When he leaves the second casino, he has twice as much money before he started gambling there. When he pays anothe $5 for parking when he goes to a third casino, he finds out he has no money left. What is the value of k?