Which ph represents a solution that releases 100 times less hydrogen ions than a ph of 9?

The equation relating pH and the concentration of H + ions is written below:

pH = - log[H+]

So, if pH = 9

9 = - log[H+]

[H+] = 1*10⁻⁹

The ratio of the larger H + to the lesser H + should be 100.

1*10⁻⁹/[H+] = 100

[H+] = 1*10⁻¹¹

pH = - log[1*10⁻¹¹] = 11