To determine how many nights it will take Niall to finish the book, we first need to find out how many pages he has left to read.
- Total pages in the book: 520 pages
- Pages already read: 100 pages
- Pages left to read: 520 - 100 = 420 pages
Next, we divide the number of pages left by the number of pages he plans to read per night:
- Pages per night: 60 pages
- Nights needed to finish: 420 pages รท 60 pages/night = 7 nights
Therefore, it will take Niall 7 nights to finish the book.