Answer :
It is necessary to employ the compound interest formula.
[tex]A=P\cdot e^{rt}[/tex]A=3P (data question), therefore:
[tex]\begin{gathered} A=P\cdot e^{rt} \\ 3P=P\cdot e^{0.04\cdot t} \\ 3=e^{0.04\cdot t} \\ \ln 3=0.04t \\ t=\frac{\ln 3}{0.04}=25\cdot1.0986=27.5 \end{gathered}[/tex]t=27.5