An annuity costs $70,000 today, pays $3,500 a year, and earns a return of 4.5 percent. What is the length of the annuity time period? 54.96 years 49.48 years 52.31 years 43.08 years 48.00 years. I got this answer

"The formula is as follows: PV of Annuity = P [ {1 - (1+r)^-n}/r] where PV of Annuity = 70,000; P=3,500; r=4.5% and =? 70,000 = 3500 [ {1 - (1+.045)^-n}/.045] Therefore n = 52.31 years." But can someone do out the math, maybe in an excel type table with each side of the equation in one cell? Because when I try to do it out I get something completely wrong.