A man loses all his money at a Las Vegas casino and decides to end his life. If he were to jump from the second floor, he would fall 20 feet. If he were to jump from the third floor, he would fall 30 feet. Each floor higher would add another 10 feet to the distance of the fall. How many feet would the jumper fall if he jumped from the 20th floor?

Answer
190 feet. There are no 13th floors in some hotels, so the 20th floor is actually the 19th.