Answer:
books.
Step-by-step explanation:
We have been given that Hannah's school hosted a book donation.
Total number of students = 150.
Total number of books donated by all students = b.
Since we know that average is calculated by dividing the sum of the values in the set by their number.


Since we are told that Hannah donated 3 times as many as the average number of books each student donated. So books donated by Hannah will be:

Upon simplifying we will get,

Therefore, Hannah donated
books.