Wednesday, February 29, 2012

Place 3 identical coins

In how many ways 3 identical coins can be placed in 5x5 grid so that no two coin come in same row and same column

1 comment:

  1. First coin can be placed in one of 25 places. For second, only 16 places are possible because of the same column and same row condition. Similarly, only 9 places for third coin. So, total ways = 25 * 16 * 9. but since coins are identical you can't distinguish one from another and thus final answer is ( 25*16*9 ) / 3 = 1200.

    ReplyDelete