I am not sure why my previous post was deleted. But, just in case you didn't see it, sqrt(12) can be written as sqrt(4) * sqrt(3). Sqrt(4) is simply 2. Therefore, we can write sqrt(12) as 2*sqrt(3).
Thus we can write the expression as 2sqrt(3)/4, which can further be simplified to sqrt(3)/2.
3/12 can be simplified to 1/4. Therefore the answer can be written as sqrt(12)/4. Hope that helps.