please answer these three they have connection to eachother

QUESTION 21 On April 1, 2014, Mark and Janet purchased a home for $240,000 with a down payment of $20,000. They obtained a very favourable 25 year mortgage with monthly payments and interest at 3.6% compounded semi-annually. How much are their monthly payments if payments are made at the end of the month? For the toolbar, press ALT+F10 (PC) or ALT-FN+F10 (Mac). BIUS Paragraph Arial 14px E I A O WORDS WERED VITIN QUESTION 22 Refer to Question 21. At the end of each month beginning in April 2014 Mark and Janet were also able to save $200, which earned interest at 24% compounded monthly, How much would they have saved on March 31, 2017 For the toolbar, press ALT+F10 (PC) ALTEFNF10(Mac 5 Paragraph Alal I III 111 QUESTION 23 Refer to Questions 21 and 22. On April 1, 2019. it had been five years and their mortgage was now up for renewal, Unfortunately, Interest rates had risen to 7,8 compounded semiannually. Mark and Janet decided to put all of their savings towards the principle at that time. However they could not fully pay off the mortgage of payments are still made at the end of the month determine their new monthly payments For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac) BIUS Paragraph AM 14 !!! =