Question 464204
<pre>
A die is rolled 4 times. find the probability of 
two 1's, one 2, and one 3.

The probability of rolling the sequence 1,1,2,3 is {{{(1/6)^4=1/1296}}}.

But that sequence could be in any order, and the 
number of ways of arranging 1,1,2,3 since the 
two 1's are indistinguishable, is {{{4!/2!=24/2=12}}}

Therefore the desired probability is {{{12*expr(1/1296)=12/1296=1/108}}}. 


Edwin</pre>