Explanation:
Question 3) there's 60 minutes in a hour
3 times 60 = 180 books in 1 hour
3 times 180 = 540 books in 3 hours
540 + 180 + 180 = 900 books in 5 hours
The difference between those numbers : 900-540= 360 and 540-180= 360 so every 2 hours 360 books is done each time so just add 360 books each time for every 2 hours added