How many combinations exist of the letters w, x, y, z, taking two at a time?

The binomial coefficient

Tells you that there are 6 ways of choosing a subset of two letters from the four given letters.

For each of these subsets there are two combinations (you can interchange the two letters: say that you choose the subset wz, you have the two combinations wz and zw)

So, there is a total of 12 combinations of the letters w, x, y, z, taking two at a time.

for the first question it would be the second answer for the second question it would be the third answer and for the third question it would be the first answer

step-by-step explanation:

2

step-by-step explanation: