Jon has to pay $9 for admission and $2 for skates for the first hour. This means so far he has paid $11. Now u have to add $2 for each hour that he skates. Remember, he only had $19 so u would stop adding $2 until u hit $19. After you keep adding $2 for every hour, you would end up with 5 hours.
When your losing weight after consuming more calories, you need to increase physical activity to increase the number of calories your body uses for energy.