b.) For A, sn = n/2(2a + (n - 1)d) s20 = 20/2(2(20000) + 1000(20 - 1)) = 10(40000 + 19(1000)) = 10(40000 + 19000) = 10(59000) = $590,000 For B, sn = a(r^n - 1)/(r - 1) s20 = 20000((1.04)^20 - 1)/(1.04 - 1) = 20000(2.191 - 1)/0.04 = 20000(1.191)/0.04 = 23822.46 / 0.04 = $595,561.57
c.) Using a graphing calculator, it takes 18 years for the <span>total amount earned a company B is greater that the total amount of earned at company A.</span>
