Question

How many no. of 4-letter strings can be formed by the letters {A,B,C,D,E,F} with no repetitions and A cannot be the first letter?

(Thinking)

My Answer

I know the total no. of 4-letter strings with no repetitions is6x5x4x3=360

Then it comes to the next consideration: how many no. of combination with A being the first letter...

Should it be5x4x3=60?[/SIZE]

Then the answer is360-60=300

Not sure if this is correct ...