How many permutations of the letters ABCDEFGH

A. Contain ED

  • I thought of ED as one letter and the rest as separate.

then there is only one way to make ED = 1! and 7! ways to rearrange them together= 7!

Answer: 7!1!= 5040

I think the same concept can be used for the rest.

E .

  • you can count CABED as one word

4!

F. Not possible 0

This is a great way to think about it, and it's how I did it. --Norlow 22:14, 17 September 2008 (UTC)

Alumni Liaison

Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood