Question

Find the number of possible call letters to a radio station (7 letters long) if the first letter must be a W or a K and no letter is repeated.

Answer 1

255,024,000 possible call letters.

Explanation:

call letters to a radio station is 7 letters long

the first letter must be a W or a K . No letters are repeated.

First letter have only two possibility.

Total of 26 letters in alphabet. First letter must be W or K. So remaining 25 letters.

Remaining 6 letters can be any alphabet (25 letters)

No letters are repeated. So second letters have 25 possibility

Third letter have 24 possibility and so one

`2 \cdot 25 \cdot 24 \cdot 23 \cdot 22 \cdot 21 \cdot 20=255024000`

So, 255,024,000 possible call letters.