Solution A is 100 times as acidic as solution B. What is the difference in pH values of solution A and solution B

The difference is 2 pH units.

Explanation:

Let's give an arbitrary value to the H⁺ concentration of solution A, [H⁺]ₐ:

If that's the case then the pH of solution A would be:

The H⁺ concentration of solution B ( [H⁺]ₓ ) is 100 higher than that, so:

And its pH:

So the difference in pH values is: