$240000 loan amount.
1) 30 years fix @4.875%. The monthly payment is about $1270. total interest paid at the end of term is $217,235
2) 5 year arm @3.75%, and 8.75% after 5 years. Assume your monthly is $1270 after 5 years, You need to pay $1978 monthly in the first 5 years to finish the payment in 30 years. The total interest paid is $260,449.