Answer
$e^{3/5}$
Work Step by Step
Given: $\Sigma_{n=0}^{\infty}\dfrac{3^{n}}{5^{n}(n!)}$
which can be written as
$\Sigma_{n=0}^{\infty}\dfrac{(3/5)^{n}}{n!}$
As we know $e^{x}=\Sigma_{n=0}^{\infty}\dfrac{x^{n}}{(n!)}$
Then,
$e^{3/5}=\Sigma_{n=0}^{\infty}\dfrac{3^{n}}{5^{n}(n!)}$
