Suppose you draw $1$ athlete at random from a group of $100$ athletes such that:
$\{$$30$ swim$\}$, $\{$$44$ run$\}$, $\{$$9$ swim and run$\}$,$\{$$5$ swim, bike and run$\}$, $\{$$11$ swim and bike$\}$, $\{$$10$ bike and run but do not swim$\}$, and $\{$$35$ only bike$\}$.
Let $S, B,$ and $R$ denote the events that the athlete you draw $\text{Swims}$, $\text{Bikes}$, and $\text{Runs}$, respectively. I give the following probabilities: $$P (S \cup R) = \frac{55}{100} + \frac{68}{100} - \frac{9}{100} = \frac{114}{100} $$ $$P (S \cup B) = \frac{55}{100} + \frac{61}{100} - \frac{11}{100} = \frac{105}{100}$$ Did I do something wrong?

No probability can be greater than $1$.
I think, for instance, the $5$ who swim and run are also included among the $30$ who swim, and the $44$ who run.