Solution
Given
[tex]\begin{gathered} N=\frac{51}{100}\times N_0 \\ \\ N=\frac{51}{100}\times N_0 \\ \\ N=0.51N_0 \\ \\ \end{gathered}[/tex][tex]\begin{gathered} N=N_0e^{-kt} \\ \\ 0.51N_0=N_0e^{-0.0001t} \\ \\ 0.51=e^{-0.0001t} \end{gathered}[/tex]Solve for t using natural logarithm
[tex]\begin{gathered} \log_e0.51=-0.0001t \\ -0.6733=-0.0001t \\ t=-\frac{0.6733}{-0.0001} \\ \\ t=6733.44 \\ t=6733 \end{gathered}[/tex]