Question

How many combinations exist of the letters W, X, Y, Z, taking two at a time?

04
06
012

Answer 1

Explanation:

C(4,2)

Use combinations formula,

c(n,r)=n!/r!(n-r)!

c(n,r)=4!/2!(2!)

`c = (4 * 3 * 2 * 1 )/(2 * 1 * 2 * 1)`

`c = 3 * 2 * 1`

`c = 6`