Answer: 50 Books
Step-by-step explanation:
B = number of books in Ruben's collection BEFORE he bought new ones.
So 6 books were bought which increased his collection by 12%.
12% as a decimal would be 0.12..then we add the variable which represents the number of books, 0.12B.
So then we know 0.12=6
*We need to isolate the variable* So we would divide 0.12 on both sides. 0.12/0.12 and 0.12/6 which is 50.
Hope this helps! :)
