Answer:
[tex]t=19.25\ years[/tex]
Step-by-step explanation:
we know that
The formula to calculate continuously compounded interest is equal to
[tex]A=P(e)^{rt}[/tex]
where
A is the Final Investment Value
P is the Principal amount of money to be invested
r is the rate of interest in decimal
t is Number of Time Periods
e is the mathematical constant number
we have
[tex]t=?\ years\\P=x\\r=3.6\%=3.6/100=0.036\\A=2x[/tex]
substitute in the formula above
[tex]2x=x(e)^{0.036t}[/tex]
solve for t
simplify
[tex]2=(e)^{0.036t}[/tex]
Apply ln both sides
[tex]ln(2)=ln[(e)^{0.036t}][/tex]
Applying property of exponents
[tex]ln(2)=[0.036t]ln(e)[/tex]
Remember that ln(e) =1
[tex]ln(2)=[0.036t][/tex]
[tex]t=ln(2)/[0.036][/tex]
[tex]t=19.25\ years[/tex]