No code please, must show work. Thank you.

Suppose you are playing game of shooting balloon. You expect to shoot n balloons in the board, assuming you are sharpshooter, 100% hit. There are two scenarios, you need find the appropriate Big-Oh notation for the following question. Note that one unit of work is shooting one balloon. "For every five balloons you can shoot, two new balloons are inserted in the board. So, if there were 20 balloons, after you shoot the first five, there are 17 on the board. After you shoot the next five, there are 14 on the board. How many balloons do you shoot before the board is empty? Note: Find your answer as a function of n. Don't just justify on the number 20 since it is just an example