An aquarium has a special penguin exhibit. The table shows the cumulative number of visitors to the exhibit at various times one Saturday. No visitors are allowed to enter the exhibit after 4:40 p.m., and the same number of visitors can enter the exhibit over each 20 minute period. How many visitors can the aquarium expect came to the penguin exhibit that day?
![An aquarium has a special penguin exhibit The table shows the cumulative number of visitors to the exhibit at various times one Saturday No visitors are allowed class=](https://us-static.z-dn.net/files/d88/fb982e2a438ac82b956d0d6c4cd83a3e.png)