Does anyone understand Doubling?
Use the approximate doubling time formula (rule of 70) for the case described below. Gas prices are rising at a rate of 0.3% per month. What is their doubling time? By what factor will prices increase in 2 years? In 8 years?
What is it's doubling time in months?

Aaron invested a total of $4,100, some in an account earning 8% simple interest, and the rest in an account earning 5% simple interest. how much did he invest in each account if after one year he earned $211 in interest? select one: a. $200 at 8%, $3,900 at 5% b. $3,200 at 8%, $900 at 5% c. $900 at 8%, $3,200 at 5% d. $3,900 at 8%, $200 at 5%