If you invest $10,000 today and it grows at annual rate of 15%

If you invest $10,000 today and it grows at annual rate of 15% (compound monthly), how many months will it take to grow to $20,000?

a. 63.51 months

b. 59.51 months

c. 55.80 months

d. 50.00 months

You buy a house at $800,000 today. You put a down payment of 20% and borrow a fixed rate mortgage of $640,000 with monthly payments and annual interest rate of 3.5% for 30 years. After 5 years, market interest rate goes up to 6.5%. How much money will you make from the mortgage for the next 25 years and the market rate remains at 6.5%?

a. 94,966

b. 99,431

c. 140,431

d. 188,431