Please help me to answer questions 2,3 and 4

2) Your son needs $100,000 in 10 years for college education. If you can earn 5% a year, how much do you need to invest today? 3) You have invested $10,000 in the stock market today; the long term expected return from the market is 10%. How much money you can expect to have in 10 years? 4) You invested $100,000 25 years ago in a company's stock. Today the value is $300,000. What's the compound rate of return over this period for the stock