Question

In how many ways can the letter of word number taken two at a time

Answer 1

So the number of ways of choosing two distinct letters at a time is (42)=6. We can then add the duplicate pairs which are O,O and N,N to give a total of 8 possible pairs.

Answer 2

15

Explanation:

There are 6 letters in the word number

This is 6 choose 2

This is a combination

The formula is 6! / ( 2! * (6-2)! )

6! / 2! 4!

(6*5*4*3*2*1) / ( 2*1 * 4*3*2*1)

Canceling like factors

(6*5) / ( 2*1)

30/2

15

There are 15 possible ways to have 6 choose 2