In a 5/1 hybrid adjustable-rate mortgage (ARM), the initial interest rate is fixed for 5 years, then is adjusted annually. (You usually pay points up front at closing in exchange for the rate lock for the first 5 years.) Suppose that you buy a house with a $ 310000, 30 year mortgage with a 5/1 ARM with initial rate of 5.75%; and suppose that five years later, the interest rate goes up to 10.15%. 

Use the Bankrate amortization schedule online to determine what your monthly payment was, originally, at 5.75%?

 Monthly Payment = 

What is your new payment? (Careful: the amount of the loan is no longer $ 310000 and you only have 25 years to pay it off.) 

New Monthly Payment =