You can put this solution on YOUR website! How long does it take $1500 to double if its invested at 4% interest, compound monthly?
Let t = time in years for this to happen
Use the compound interest formula
1500(1+)^(12t) = 3000
(1.00333)^(12t) = 2
Use logs here
12t = 208.3
t = 17.36 years to double at 4%