Ahmed purchased a $$100,000$ villa by taking a loan from a bank with an interest rate of $12\%$ compounded monthly and was agreed to be paid back through monthly payments over $20$ years.

a$.$ If the villa is sold after $8$ years for $$125,000,$ how much equity does the individual have? $($Equity is the difference between the current market value and the balanced owed on the loan$).$

b$.$ Of the total amount paid on the loan, what portion was principal and what portion interest?