Probability of no two of the marbles drawn have same color A bag contains 10 blue marbles ,20 black marbles , 30 red marbles.A marble is drawn from the bag, its colour recorded and it is put back in the bag. This process is repeated 3 times .The probability that no two of the Marbles drawn have the same color?
If 3 repeated events are independent then $\frac {10}{60}\times\frac {20}{60}\times\frac {30}{60}=\frac 1{36}$
But the answer is $\frac 1 6$. How do you get this?

First, you may pick blue-black-red. Arrangement of this colours is 3!. Total probability is Your answer * 3!. i.e 1/6. 
