We know that Joy can read 8 pages of a book in 20 minutes, or 8/20 pages per minute.
To find out how many minutes it will take her to read x pages, we can use the formula:
time = (number of pages) / (pages per minute)
Substituting 8/20 for "pages per minute", we get:
time = x / (8/20) = (20/8) * x = 2.5x
We are given that the time it takes Joy to read x pages is 5 hours, or 300 minutes, so we can write: 2.5x = 300
Solving for x, we get: x = 120.
The value of x is 120.
#### 120
The answer is: 120
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Joy can read 8 pages of a book in 20 minutes. How many hours will it take her to read x pages?
If we know the answer to the above question is 5, what is the value of unknown variable x?

### Answer:
