please answer questions 19 and 22

Sinking Fund Find the interest rate needed for the sinking fund to reach the required amount. Assume that the compounding period is the same as the payment period. (See Example 6.) 248 CHAPTER 5 Mathematics of Finance 19. $50,000 to be accumulated in 10 years; annual payments of $3940. 20. $100,000 to be accumulated in 15 years; quarterly payments of $1200. 21. $38,000 to be accumulated in 5 years; quarterly payments of $1675. 22. $77,000 to be accumulated in 20 years, monthly payments of $195. 23. What is meant by a sinking fund? List some reasons for estab- lishing a sinking fund. 24. Explain the difference between an ordinary annuity and an annuity due