To determine the probability that Max and Ava will have an odd number of push-ups three times in a row, we first need to find the probability of getting an odd number on a single spin of the spinner.
The numbers on the spinner are 1, 2, 3, 4, 5, 6, 7, and 8. Among these, the odd numbers are 1, 3, 5, and 7. This gives us a total of 4 odd numbers.
The total number of outcomes when spinning the spinner is 8 (since the numbers are 1 through 8). Therefore, the probability of spinning an odd number is calculated as follows:
\[ P(\text{odd number}) = \frac{\text{Number of odd outcomes}}{\text{Total outcomes}} = \frac{4}{8} = \frac{1}{2} \]
Next, we want to find the probability that they will get an odd number three times in a row. Since the spins are independent, we can multiply the probability of getting an odd number for each spin.
Thus, the probability of getting an odd number three times in a row is:
\[ P(\text{3 odd numbers}) = P(\text{odd}) \times P(\text{odd}) \times P(\text{odd}) = \left(\frac{1}{2}\right) \times \left(\frac{1}{2}\right) \times \left(\frac{1}{2}\right) = \left(\frac{1}{2}\right)^3 = \frac{1}{8} \]
Therefore, the probability that Max and Ava will have an odd number of push-ups three times in a row is:
\[ \boxed{\frac{1}{8}} \]