hi any help would be nice these problems are troublin me!!

If interest is compounded continuously, what annual rate must you receive if your investment of $2600 is to grow to $4000 in two years?

If an investment of $3500 grows to $4249.13 in four and a half years, with an annual interest rate that is compounded quarterly, what is the annual interest rate?

Lisa Chow wants to have $40,000 available in ten years for a down payment on a house. She has inherited $35,000. How much of the inheritance should be invested at 4.6% annual interest, compounded quarterly, to accumulate the $40,000?

A sum of money P that can be deposited today to yield some larger amount A in the future is called the present value of A. If A = $8,000 at 6% compounded annually for 4 years, find the present value of A. (Hint: Substitute A, the interest rate per period r, and the number t of periods in the compound interest formula and solve for P.)