The current price for a TV set is $850. At that price BestBuy store in Alexandria sells 24 TV sets a month. For every $20 the store lowers the price, it can sell an additional TV. Conversely, for every $20 it raises the price it will sell 1 TV less. What is the number of sold TV sets when the price is $785? (Only enter the nearest whole number. For example, if your answer is 4.32, only enter 4, and if your answer is 4.78, only enter 5)