Answer
40
Work Step by Step
We know that logarithms with base $e$ are natural logarithms, and $ln(x)$ can be written as $log_{e}x$.
Therefore, $10ln(e^{4})=10log_{e}e^{4}$.
We know that for all positive numbers $a$ (where $a\ne1$), and all positive numbers $x$, $y=log_{a}x$ means the same as $x=a^{y}$.
Therefore, $10log_{e}e^{4}=10\times4=40$, because $e^{4}=e^{4}$.