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I am thinking of a positive number, less than 500, that is divisible by every number from 1 to 10 (inclusive), with one exception. What number am I thinking of? Prove that the answer is unique. 

 

An explanation would be great!

 Mar 11, 2019
 #2
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It will be even

 

1*2*3*4*5  =  120  would be divisible by every integer from 1 - 10  inclusive except for 7 and 9

 

Multiplying this by 3  gives

 

1*2*3*3*4*5  =     1* 2*4*5*9  =  360

 

This will be divisible  by 1, 2, 3, 4, 5, 6, 8, 9, and 10......it will not be divisible by 7

 

 

cool  cool cool

 Mar 11, 2019
edited by CPhill  Mar 11, 2019
edited by CPhill  Mar 11, 2019
edited by CPhill  Mar 11, 2019

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