This question is exponential; the basic formula is
(final amount) = (initial amount) * 2^(total hours ÷ time it takes to double)
So if F = final amount and t = time in hours,
[tex]F=500*2^ \frac{t}{2} [/tex]
and for this one,
[tex]F=500*2^ \frac{24}{2} [/tex]
[tex]F=500*2^1^2[/tex]
[tex]F = 2048000 [/tex]