Given: the word is ‘SUNDAY.’

To find: number of words that can be formed with the letters of the given word, that can begin with N, and that can begin with N and end in Y

Total number of letters = 6

Formula used:

Number of arrangements of n things taken all at a time = P(n, n)

∴ Total number of arrangements

= the number of arrangements of 6 things taken all at a time

= P(6, 6)

{∵ 0! = 1}

= 6!

= 6 × 5 × 4 × 3 × 2 × 1

= 720

Hence, the total number of words can be made by letters of the word ‘SUNDAY’ = 720

Now, we need to find out of a number of words starting with N

So, fix the position of the first letter as N:

Remaining number of letters in the word ‘SUNDAY’ = 5

Now, we need to arrange these 5 letters at 5 places.

Formula used:

Number of arrangements of n things taken all at a time = P(n, n)

∴ The total number of ways

= the number of arrangements of 5 things taken all at a time

= P(5, 5)

{∵ 0! = 1}

= 5!

= 5 × 4 × 3 × 2 × 1

= 120

Hence, the possible number of words using letters of ‘SUNDAY’ starting with ‘N’ is 120

Now, we need to find out a number of words starting with N and ending with Y

So, fix the position of first and last letter as N and Y:

Remaining number of letters = 4

Now, we need to arrange these 4 letters at 4 places.

Formula used:

Number of arrangements of n things taken all at a time = P(n, n)

∴ The total number of ways

= the number of arrangements of 4 things taken all at a time

= P(4, 4)

{∵ 0! = 1}

= 4!

= 4 × 3 × 2 × 1

= 24

Hence, the possible number of words using letters of ‘SUNDAY’ starting with ‘N’ and ending with ‘Y’ are 24