Respuesta :

Percentage increase = Final - Initial / Initial   * 100
% increase = 500 - 250 / 250 * 100
% increase = 250 / 250 * 100 = 100

In short, Your Answer would be 100%

Hope this helps!
You have to know the time.
If it doubled in a year, the rate is 100%
If it doubled in 2 years, the rate is 41.4214%
If it doubled in 3 years, the rate is 25.9921%
If it doubled in 10 years, the rate is 7.17735%