Math Is Fun Forum

chetah

Member

Registered: 2008-02-15

Posts: 32

Permutations and Combinations

Over the internet, data are transmitted in structured blocks of bits called datagram’s.
1.    In how many ways can the can the letters DATAGRAM be arranged?
2.    For the arrangements in part 1, how many has all three A’s together?

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Permutations and Combinations

You should be able to do #1 yourself. I believe it’s on #2 that you’re stuck. For this question, treat AAA as a single letter, say Ā. Hence you need to find how many ways the letters D, Ā, T, G, R, M and be arranged.

By the way, Chetah: are you just posting your homework questions and asking us to do your homework for you? It’s all very well copying the solutions we give but it’s much more important to understand the working behind the solutions we post.

chetah

Member

Registered: 2008-02-15

Posts: 32

Re: Permutations and Combinations

These are not my assignments.  These are questions I am working on in preparation for my exams.  Would you like me to post my solutions?

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Permutations and Combinations

Yes!  Always post any work you have done on a problem, even if you are uncertain of it or if it is just a guess.  I typically don't answer any post that looks like "do this homework for me", and if I do, I never give out any where near a full solution.  And certainly all of your posts look like that.  Furthermore, letting us see your method will help formulate our responses and correct any errors in thinking.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."