Final answer:
Without the original loan amount, it is not possible to calculate the exact time it will take to pay off the loan by paying an extra $250 per month. More information is required to perform such a calculation.
Step-by-step explanation:
To determine how long it will take to pay off a student loan by paying an extra amount each month, you can use an amortization formula or a financial calculator. However, because the original loan amount is not provided, we cannot calculate the exact time it will take to pay off the loan. If you were to add an extra $250 to your monthly payments, the loan would certainly be paid off faster than the original term, but without more information, we cannot provide a specific timeframe.