Answer:
Hanna donated b/50 books
Explanation:
In this problem, we have:
n = 150 number of students at Hanna's school
b = ? number of total books donated by the students
Also, Hannah has donated 3 times as many as the average number of books each student donated.
The average number of books each student donated can be written as:

And calling
h = number of books donated by Hannah
This means that

Simplifying, this can be rewritten as
