Finance-Please Help!!! I do not understand any of this. Please explain! All help will be greatly appreciated!

Approximately how many years are needed to double a $500 investment when interest rates are 10 percent per year?

Approximately what interest rate is earned when an investment doubles over 12 years?

Which cash flow would you rather pay, $425 today or $500 in two years if interest rates are 10 percent? Why?

What is the value in year 15 of a $250 cash flow made in year 3 if interest rates are 11 percent?

What annual rate of return is earned on a $1,000 investment when it grows to $1,800 in six years?

How long will it take $2,000 to reach $5,000 when it grows at 10 percent per year?

At age 25 you invest $1,500 that earns 8 percent each year. At age 40 you invest $1,500 that earns 11 percent per year. In which case would you have more money at age 65?

What annual rate of return is implied on a $2,500 loan taken next year when $3,500 must be repaid in year 4?