### Chork's Puzzle 52

Trying to earn some extra cash, Roland decided to open a lemonade stall.

On his first day, he only managed to sell 16 cups of lemonade. The next day wasn't any better. It was raining really heavily and few people passed by his stall, so he only managed to sell 8 cups.

After reviewing his performance for the past 2 days, he decided to decorate his stand to make it look more attractive so that it will draw more people to his lemonade stand. His publicity stunt worked, for he managed to sell 33 cups of lemonade the next day.

Soon, word went round that there is a new lemonade stall selling cheap and nice lemonade. To Roland's surprise, sales was so good the next day that a whooping 89 cups of lemonade were sold. On the fifth day, Roland's good sales continued - he managed to sell 78 cups of lemonade.

It was soon obvious that Roland's sales were following a certain pattern.

A few days later, it was the first time after the 3rd day that Roland sold less than 40 cups of lemonade.

If you know the answer, post it in the comments section of this post.