Answer
$t=12$ seconds
Work Step by Step
Step 1: The formula to be used here is $s=rwt$.
Step 2: After substituting the values of $s$,$r$ and $w$ provided by the question into this formula, the equation becomes $6\pi=2\times \frac{\pi}{4}\times t$
Step 3: Simplifying, $6\pi=\frac{\pi}{2}\times t$
Step 4: Multiplying both sides by $\frac{2}{\pi}$,
$6\pi\times\frac{2}{\pi}=\frac{\pi}{2}\times t\times\frac{2}{\pi}$
Step 5: Simplifying, $t=12$ seconds
