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 175 and 120 is 55.

Next, we need to find what percentage of the original number the absolute difference represents. To do this, we divide the absolute difference by the original number (in this case, 175) and then multiply by 100 to get the percentage.

So, the percentage difference between 175 and 120 is:

Absolute difference = 175 - 120 = 55

Percentage difference = (Absolute difference / Original number) x 100
= (55 / 175) x 100
= 31.43%

Therefore, the percentage difference between 175 and 120 is 31.43%. This means that 120 is 31.43% less than 175.