Finding the Actual Doubling Time (Logarithms and Exponential Models)
This problem involves the Rule of 70, which gives quick estimates of the doubling time of an exponentially growing quantity. If r% is the annual growth rate of the quantity, then the Rule of 70 says
Doubling time in years =(aprox) 70/R
Use the Rule of 70 to estimate how long it takes an $8000 investment to double if it grows at the annual rate 2%. Compare with the actual doubling time.
Round your answer for the actual doubling time to three decimal places.
The doubling time estimated with the rule of is: I got this one, 35.
The actual doubling time is Entry field with incorrect answer years.
I'm not sure how to go about this.