Question 470200
The tree diagram will look like the following (of course, you may have it oriented a different way)


<img src="http://i150.photobucket.com/albums/s91/jim_thompson5910/Algebra%20dot%20com/tree_diagram7-13-2011.jpg">



Sample space: 


{369T,396T,639T,693T,936T,963T,369R,396R,639R,693R,936R,963R}



There are 6 plates with a T in them and there are 12 plates total. So probability is 6/12 = 1/2