Answer
$12$ 2-permutations
Work Step by Step
A 2-permutation means selecting 2 elements from the set and arranging them in every possible order. Since the set has 4 elements, the number of 2-permutations is:
$P(4,2)=4\cdot 3=12$
The 2-permutuations of set {W,X,Y,Z} are:
(W,X), (W,Y), (W,Z),
(X,W), (X,Y), (X,Z),
(Y,W), (Y,X), (Y,Z),
(Z,W), (Z,X), (Z,Y)
