Please provide formula and solution

20. Bank A shows information about loan-type financial products. It shows the nominal interest rate of 17% with the condition of compounding interest semi-annually. What is the real interest rate? EAR is equal to % (specify 2 decimal places) 21. Save 3000 baht per month for 38 years, invest in stocks or assets that yield 8% annually. How many years will there be money to spend 80000 per month