To determine how many pages Henry reads per minute, we can use the following calculation:

Henry reads 90 pages in 30 minutes (half an hour). So, we can divide the number of pages by the number of minutes:

$\text{Pages per minute} = \frac{90 \, \text{pages}}{30 \, \text{minutes}} = 3 \, \text{pages per minute}$

Therefore, Henry reads 3 pages per minute.

Would you like more details or have any other questions?

Here are 5 related questions:

1. How many pages does Henry read in one hour?
2. If Henry slows down by half, how many pages will he read in 15 minutes?
3. How many pages will Henry read in 45 minutes?
4. If Henry reads 5 pages per minute, how long will it take him to finish a 150-page book?
5. What is the total time Henry will take to finish a 120-page book at his current reading speed?

Tip: To find the rate of anything, divide the total amount by the time taken!