Question

How long will it take any investment to quadruple if it earns 5.6% interest, compounded continuously

Answer 1

For this example we will calculate $100 becoming $400
Years = natural log (Total / Principal) / rate
Years = natural log (400 / 100) / .056
Years = natural log (4) / .056
Years = 1.3862943611 / .056
Years = 24.7552564482
(Roughly 24 (3 / 4) years)