Answer
The number of ways in which jokes can be ranked from the best to the worst is $720$.
Work Step by Step
We know that the Fundamental Counting Principle says that the number of ways in which a series of things occurs in succession can be computed by multiplying the number of ways in which they may occur.
From the provided information, the numbers of ways that such jokes can be ranked from best to worst are:
(Using Fundamental Principle of Counting)
$\begin{align}
& 6!=6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1 \\
& =720
\end{align}$
