To find the percentage difference between two numbers, we first need to find the absolute difference between them. In this case, the absolute difference between 39 and 27 is 12 (39-27=12).

Next, we need to find the average of the two numbers. The average of 39 and 27 is (39+27)/2 = 33.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 39 and 27 is (12/33) x 100 = 36.36%.

Therefore, the percentage difference between 39 and 27 is 36.36%. This means that the two numbers are quite different from each other, with one being 36.36% higher than the other.