Answer:
It is incorrect.
Explanation:
It says that she bought 18 books, and she bought 3 times as many books as Austin. The thing that made you mess up the answer is that you thought you needed to multiply, but you needed to divide.
To find the number of books Austin purchased, we will do a simple division problem.
18 ÷ 3 = 6
The number of books Austin bought is 6, which means that b = 6
Oh, and for a, the equation should be 18 = b x 3