Interest rates are 18% per annum compounded monthly in this entire problem.

a. Betty and Bob deposit $100 into a Sinking Fund at the end of each month for 20 years. Algebraically find the account value at the end of the 20 years. Your final answer should be correct to 3 places after the decimal point.

b. Bertha purchases a house for $200,000 with a 20 year mortgage of end of month payments. Algebraically find what the monthly payments are. Your final answer should be correct to 3 places after the decimal point.