Answer: 17 years
Step-by-step explanation:
Exponential equation for compund amount( compunded continuously):
[tex]A=Pe^{rt}[/tex] , where P= Principal value , r= rate of interest , t= time.
Given: A= 2P
r =4%= 0.04
To find : t
Substitute all values in the formula , we get
[tex]2P=Pe^{0.04t}\\\\\Rightarrow\ 2=e^{0.04t}[/tex]
Taking natural log on both sides
[tex]\ln2=\ln e^{0.04t }\\\\\Rightarrow\ 0.693147=0.04t\\\\\Rightarrow\ t=\dfrac{ 0.693147}{0.04}\\\\\Rightarrow\ t=17.3286\approx17[/tex]
hence, it will take 17 years (approx).