solve without using excel please and thank you

Question 2 How many years will it take for an amount of $2,000 to double if invested at an interest rate of 8% APR compounded quarterly? Question 3 An individual wishes to deposit an amount of money now and $100 every six months so that at the end of five years $1,800 will have been accumulated. With interest at 6% per year, compounded semiannually, how much should be deposited now? Question 4 A sum of $5,000 is deposited now, $3,000 three years from now, and $1,000 each year from years 4 through 10. Determine the future worth of these deposits at the end of year 10 at an interest rate of 10% per year