We can calculate an experimental probability by repeating a experiment or trial and computing the number of positive results.
In this case we have to perform N=50 trials.
A positive case is when we get Red in the spinner.
Then, if we get Red, for example, 5 times out of the 50 trials, we can calculate the probability as:
This is our estimation of the probability of getting Red in the spinner and has a value of P(red)=0.1=10%.
Answer: P(red)=0.1.
As it is a sample result, it can vary from sample to sample. This probability is an estimation of the real probability of getting red in the spinner.