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How many positive five digit numbers have a 1, 3, 7 or 5 in them?

 Aug 21, 2023
 #1
avatar+126966 
+1

Counting the  number of positive 5-digit numbers that  don't  contain an  odd digit = 

 

4 choices for the  1st digit  *   4 choices for each of the  other 5 digits  = 

 

4 * 5^4  =  2500

 

So the number of  positive 5-digit numbers containing at  least 1 odd  digit = (90,000 - 2500)  =

 

87500

 

EDIT TO CORRECT A MISTAKE !!!!

 

cool cool cool

 Aug 22, 2023
edited by CPhill  Aug 22, 2023
edited by CPhill  Aug 22, 2023
edited by CPhill  Aug 22, 2023
edited by CPhill  Aug 22, 2023
 #2
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0

Cphill:

 

I think you made a typo in 5-digit numbers.

 

There are: 99,999  -  10,000  +  1 ==90,000 5-digit integers, and not 900,000.

 Aug 22, 2023
 #3
avatar+126966 
0

Thx....since corrected  !!!

 

cool cool cool

CPhill  Aug 22, 2023

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