+422 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...
+129852 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
