need help again!!!

[PDUTCHY]

I probably should know this but what are the steps you would take to
find out how many possible number combos you can make with a certain
amount of digits (1 thur 9) making 3 digit numbers. 241 or 635
etc...etc... and you can't use the digits like this 223 or
333.(repeating the same digit in the number) Please help me
soon....

THANKS

 

[Frank Kabel]

Hi
you already received to answers in public.excel
in your case there're
9*8*7 = 504
different combinations without a repeating number.
Just imagine a basket with 9 balls (each representing a number from
1-9):
- for taking out the first ball there're 9 different possibilities
- for the second one there're only 8 balls left -> only 8 possibilities
- for the third ball only 7 different balls are in the basket

If you allow repetitions just imagine that you put the ball back into
the basket after you have chosen one. Therefore
9*9*9 = 729 possibilities

for more information you may search Google for a good statistic site
(or have a look at an introductionary mathematical book about
statistic)

P.S.: I hope this isn't homework

 

[Gord Dibben]

Frank

OP's request has changed from first time around.

Now he's not allowing same two digits in a 3-number permutation.

i.e. States that 223 is not allowed.

and you can't use the digits like this 223 or
333.(repeating the same digit in the number)

I would assume by that rule 224, 225 etc. would also be invalid.

Or 232, 323, 332 and a whack of others.

Gord