There are two players A and B. They each play a game against a third player C. Player A has a 50% chance of winning, whereas player B has an 80% chance of winning.
I want to use a sentence to say how much better is player B at beating player C, compared to player A. I came up with:
Player B is __% better at beating player C than player A.
The problem is, I don't know what to put in the blank. Do I put 30 or 60?
If you look at the the difference between the probably of winning a game against C, it is 30%.
$$ 0.8-0.5=0.3 $$
But the percentage difference between 50% and 80% is 60%.
$$ \dfrac{0.8-0.5}{0.5}=0.6 $$
So should I use the percentage difference or just the difference in the above sentence?
If the sentence is actually ambiguous, how can I unambiguously compare players A and B without mentioning their actual probabilities?
Note: I didn't post this o ELU.SE because I am specifically asking about unambiguous, mathematical language.