John wants to by a diamond ring for his Financee and the store is offering two choices for payment: a) pay $5000 cash now or (beer) pay $250 per month over 2 years. If John interest rate is 15% annually, which is the better option and how much does John save by making the better decision?

I believe the answer is to pay the 5k now because the FV of that money is $6612.50 which would be 1,612.50 more. Can you check my math and that I am reading this correctly?