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There are no results for in the 4- by -4 grid of unit squares shown, two coins will be placed at random such that each coin is in a different unit square. what is the probability that the two coins willl not lie in the same row or column of unit squares? express your answer as a common fraction.

 

 

 

 

Grid Looks Like This...

 

    
    
    
                    
 Jan 31, 2019
edited by APatel  Jan 31, 2019
 #1
avatar+102417 
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Not sure about this...but....

 

Put one coin in any unit square

 

Then the second coin can be placed in any of the other 15 unit squares

 

But.....only 6 of them are either in the same row / column

 

So.....9 aren't

 

So......the probability that the two coins do not lie in the sane row/column = 9 /15  =   3 / 5

 

 

cool cool  cool

 Jan 31, 2019

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