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