Question 1102445
This is the compound interest formula
P=Po(1+rate/12)^120, the rate divided by 12 months in a year, and 120 compoundings.
2000=Po(1+(0.08/12))^120=Po*2.2196, but don't round.  Divide both sides by the 2.2196 and Po=$901.05
Rule of 72 would suggest doubling in 72/8 or 9 years, and this has doubled and a little more, which is consistent.