A standard six-sided die is rolled six times. You are told that among the rolls, there was one 1 two 2's, and three 3's. How many possible sequences of rolls could there have been? (For example, 1, 2, 4, 6, 3, 2 is one possible sequence.)
There are 6*5*4 = 120 ways to choose the positions of the 3's. Then there are 3 ways to choose the position of the 1, and the remaining rolls must be 2, so there are 120*3 = 360 possible sequences.
