Answer: 8
Reason:
The notation y ∈ Z translates to "y is an integer". An integer is a number that doesn't have any decimal or fractional portions. Informally we can consider them whole numbers more or less.
Set A is defined as the set of integer y values such that 6 < y < 24 and y is even.
List the even integers between 6 and 24. Exclude each endpoint because we don't have "or equal to" as part of the inequality signs.
A = {8, 10, 12, 14, 16, 18, 20, 22}
Count the number of items inside set A.
There are 8 values in that list. Therefore, |A| = 8 is the final answer.
The notation |A| counts out the number of items inside set A. It is known as the cardinality of the set.