The two-digit whole numbers are the numbers from 10 to 99, inclusive.
We want to find the probability that the square root of a randomly selected two-digit whole number is less than eight.
The square root of a two-digit whole number is less than eight if and only if the two-digit whole number itself is less than 64 (since the square root of 64 is 8).
There are 54 two-digit whole numbers from 10 to 63, inclusive.
Therefore, the probability is $\frac{54}{90} = \boxed{\frac{3}{5}}$.
The answer is: \frac{3}{5}
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
What is the probability that the square root of a randomly selected two-digit whole number is less than eight? Express your answer as a common fraction.

### Answer:
