Plug in 40,000 for p(n), then use algebra. First step divide by 18. Then you have 2222.222222=e^0.035n.
Take the natural logarithm (Ln) on your calculator of both sides:
Ln(2222.2222)=Ln(e) 0.035n
Ln2222.2222 just gives you a number and Ln(e) cancel each other so you have:
Ln(2222.222222)= 0.035n, divide both sides by 0.035 and you will find “n”(the number of years after 2000).
The second method is trial and error, keep plugging in numbers for n starting at “1” and see what number gets you closest to 40,000 when you calculate the equation