Ensembles, sports et expression écrite en anglais

In a school club, there are $50$ students in total ($N=50$). Among them, $20$ students practice swimming ($S$) and $15$ students play basketball ($B$). We know that $5$ students practice both sports. 1) Calculate the total number of students who practice at least one of these two sports using the principle of inclusion-exclusion: $|S \cup B| = |S| + |B| - |S \cap B|$. 2) Write a short paragraph in English explaining that although some students like swimming, they never play basketball.