To find the percentage difference between two numbers, we first need to calculate the absolute difference between them. In this case, the absolute difference between 20 and 35 is 15 (35-20=15).

Next, we need to find the average of the two numbers. The average of 20 and 35 is (20+35)/2 = 27.5.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 20 and 35 is (15/27.5) x 100 = 54.55%.

Therefore, the percentage difference between 20 and 35 is 54.55%. This means that 35 is 54.55% more than 20.