Answer:
|P|=24
Explanation:
The notation |P| stays for the cardinality of the set, i.e. the number of elements in the set P.
From the diagram we can see that 15 elements belong only to set P and do not belong to the set Q. 9 elements belong to both sets Q and P.
Thus, 15 + 9 =24 elements belong to the set P.
Hence, |P|=24.