Jack earns $4500 monthly income. His rent is $950.00 per month, his other bills are $250.00 per month, and his car loan requires a $580 per month.

a) If Jacks food cost $450 per week and he estimates other additional expenses to be $335 per month, how much he will have left each month to reach his financial goals?

b) Jack is considering buying a new car instead of the old one. His new car loan will be $875 per month, and the insurance will increase by $145.80 per month. Jack estimates that his other-related expenses will remain the same. What is the opportunity cost if Jack purchases the new car? (Show your calculations)