Answer:
n(A) = 5
Step-by-step explanation:
The notation "n(A)" means the "number of elements in the set A".
Note, that this has to be "unique" elements in the set. If there is five 6's, we will count as one...
Looking at the set given, there are 4, 6, 8, 10, 12 -- 5 elements. All are unique, no repetitions. Hence n(A) = 5
