1) Find the accumulated amount A, if the principal P is invested at an interest rate of r per year for t years. (Round your answer to the nearest cent.) P-$18,000, r-790, t-10, compounded quarterly 2) Find the interest rate needed for an investment of $2000 to grow to an amount of $3500 in 4 years if interest is compounded monthly. (Round your answer to the nearest hundredth of a percentage point.) 3) How long will it take $12,000 to grow to $15,000 if the investment earns interest at the rate of 5%/year compounded monthly? (Round your answer to one decimal place.) 4) Find the interest rate needed for an investment of $9,000 to quadruple in 13 years if interest is compounded annually. (Round your answer to the nearest hundredth of a percentage point.)