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A lucky integer is a positive integer which is divisible by the sum of its digits.  How many numbers from 1 to 50 are lucky?

 Nov 15, 2020
 #1
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10 , 12 , 18 , 20 , 21 , 24 , 27 , 30 , 36 , 40 , 42 , 45 , 48 , 50>> Total =  14 such numbers

 Nov 15, 2020
edited by Guest  Nov 15, 2020
 #2
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Mmmm...let's see  ( I'm not sure myself  !!!)

 

The first 9 positive integers are all divisible  by their sum

 

Then   10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50

 

I get  23    !!!

 

cool cool cool

 Nov 15, 2020
 #3
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Guest is probably correct......I don't know if we  can  consider single digits as  having a sum !!!

 

 

cool cool cool

CPhill  Nov 15, 2020

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