not sure how to solve this problem

Suppose you are buying your dream home for $350,000 and a bank is offering a loan on the full purchase price. Mortgage payment is due end of the month. Bank has two mortgage products: 30-year at 3.5% APR, or 20- year at 2% APR If you decide to go with the 20-year mortgage (instead of 30-year mortgage), how much extra will you pay monthly? Enter your answer in the following format: 123.45 Hint: Compute difference of two mortgages (i.e., 20 year - 30 year). Answer is between 181.03 and 218.83