please assist with "problem 7" please show formula used and work. thank you so much

need assistance with problem 7 only! thank you

Problem 5 In January 2012, the average house price in Kansas City was $314,600. In January 2005, the average price was $200,000. What was the annual increase in selling price? (Hint: calculate r) Problem 6 A 1000-acre ranch including a house in Southwest Missouri was sold for $10,311,500 in 2015. Unfortunately, the owner had bought the same ranch for $12,377,500 three years ago in 2012. What was the annual rate of return on that property? Problem 7 You have decided to make $4000 contribution to 401K. The rate of return (r) on the account is 11%. Assume that no additional contribution will be made to your account, what will be the difference in amount if you start contribution to your account now and retire in 45 years compared to if you wait another 10 years before contributing the same amount to your account