What is the Cardinal number n(A)?

Question

Find the Cardinal number n(A) for the set A such that A = {x | x is a number on a clock face}

a. n(A) = 6

b. n(A) = 24

c. n(A) = 3

d. n(A) = 12

Answer 1

for a layman,

n(A) is the number of elements in the set A

if you mean a clock with 1,2,...12 written on it n(A) will be 12