How long will it take for an investment to triple if interes

How long will it take for an investment to triple if interest is paid at 10%, compounded continuously?

The formula of amount compounded countinuously is

A=p *e^(r*t)

let the principal amount be $x. And after t years it becomes three times that is 3x

3x=x*e^(10t)

3=e^(10t)

taking ln on both sides

ln 3= .10t

t= ln3/.10= 10.99 that is approx 11