a) Sophie invested $205,000 to purchase a home. After 9 years, she sold the home for $300,000. Calculate the effective interest rate earned on this investment. ______% (Round to two decimal places)

b) Sophie then wondered how long will it take for an investment to at least double its original amount if it is growing at 3.25% compounded semi-annually?

years___months____

Express your answer in years and months, rounded to the next month