a We want to find out in how many ways we can arrange the letters in the word AT. To find the number of permutations of the letters in the given word, we can use the Fundamental Counting Principle.
Value of n
Number of choices for nth letter
1
2
2
1
Number of permutations
2* 1=2
Therefore, there are 2 ways we can arrange all of the letters in the word AT.
b We want to find out in how many ways we can arrange 2 of the letters in the word AT. When arranging 2 letters of the given word, we have 2 choices for the first letter and 1 choice for the second letter. Let's use the Fundamental Counting Principle one more time!
2* 1 =2
Therefore, there are 2 ways we can arrange 2 of the letters in the word AT.
