Answer
4
Work Step by Step
We first combine this into one square root:
$1/3 \sqrt {6\times 24} = 1/3 \sqrt {144}$
In order to see if a radical is in simplified form, see if any of its factors are perfect squares (meaning that their square root will be an integer). We see that 144 is a perfect square, so we know that we can simplify:
$1/3 \sqrt {144}=12/3=4$
