1. ## 3 Digit Combination

My daughter has this homework question and she doesn't believe her dear old dad....

Question: How many different 3-digit area codes can be created if no digit can be repeated?

2. ## Re: 3 Digit Combination

How much extraneous information has to be taken for granted? For example, in the country where I live, 0 (zero) can be part of an area code.

3. ## Re: 3 Digit Combination

<P ID="edit" class=small>(Edited by sdckapr on 07-Feb-05 21:14. Added PS and hid results)</P>Assuming that the first can be zero:

<span style="background-color: #FFFF00; color: #FFFF00; font-weight: bold">10*9*8= 720</span hide>

Steve
PS. If the first can not be zero then
<span style="background-color: #FFFF00; color: #FFFF00; font-weight: bold">720 - 1*9*8 = 648</span hide>

4. ## Re: 3 Digit Combination

Gary

...was her dear old dad correct...? <img src=/S/evilgrin.gif border=0 alt=evilgrin width=15 height=15>

5. ## Re: 3 Digit Combination

Steve,

How did you know that Gary was going to ask the question today!! And if you knew, why did you not post the correct answer straight off.?? <img src=/S/scratch.gif border=0 alt=scratch width=25 height=29>

6. ## Re: 3 Digit Combination

Don't forget that Steve is a WMVP. They're expected, among other things, to be able to provide answers to questions before they're asked. <img src=/S/wink.gif border=0 alt=wink width=15 height=15>

Alan

7. ## Re: 3 Digit Combination

<img src=/S/confused.gif border=0 alt=confused width=15 height=20>

I answered it and edited it yesterday (in the span of about 2 mins). The question was asked yesterday as far as I could tell, but perhaps Hans and I both used our "WMVP" powers if it were posted today...

Steve

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