Answer: She can read 1.2 chapters of her book in one hour.
Explanation:
When we have a relation of: "doing something" in a given "amount of time"
The rate at which you can do that activity per unit of time is:
R = (how much you did)/(time it took)
In this case, we know that
"Tory reads 4/5 of a chapter in 2/3 of an hour"
Then the rate, in this case, could be calculated as:
R = (4/5 chapters)/(2/3 hour) = 1.2 chapter per hour.
This means she can read 1.2 chapters of her book in one hour.