We are given that Frederick borrows $3000 at an interest rate of 2.5%. We will determine the time for this loan to gain $225. To do that we will use the following formula:

Where:

Now we solve for the time by dividing both sides by "Pr":

Now, the interest rate in decimal form is determined by dividing the percentage by 100:

Now we substitute the values:

Now we solve the operations:

Therefore, the time of the loan must be 3 years.