To find the number of bumblers when the ratio of grumblers to bumblers is 5 to 1, we can set up the following relationship:
Let \( G \) represent the number of grumblers and \( B \) represent the number of bumblers.
According to the given ratio: \[ \frac{G}{B} = 5 \]
We also know that: \[ G = 115 \]
Using the ratio, we can express \( B \) in terms of \( G \): \[ B = \frac{G}{5} \]
Now we can substitute \( G \) with 115: \[ B = \frac{115}{5} \] \[ B = 23 \]
Thus, the number of bumblers is \( \boxed{23} \).