The Solution:
Given that a bank loaned out $18000.
Let the amount loaned out at 8% per year be represented with x.
So that the amount loaned out at 16% per year will be $(18000-x)
Recall: By formula for simple interest ( since the simple interest is the same as compound interest if the period under consideration is 1 year), we have:

So, for the loan at 8% per year:

So, for the loan at 16% per year:





Cross multiplying, we get


Dividing both sides by 8, we get

Thus, the amount loaned at 8% is $4750.
Therefore, the correct answer is $4750.