Answer:
She donated b/50 books
Explanation:
In this question, we are we are told 150 students donated a total of b books. The average number of books donated by each student will be:
The total number of books/ the total number of students.
The average number of books is this b/150.
Now, we are also told that Hannah donated 3 times the average number of books.
This is simply calculated by multiplying the average number of books donated by 3
This is equal to 3 * b/150 = b/50 books
Hence, Hannah donated b/650 books