Total number of possibilities : Total_Outcome=6^6
Choose 3 dice among the six for showing the same face
selections= 6C3
Common face can take 1,2,3,4,5,6
selections= 6C3 * 6
Remaining 3 dice can take 5*4*3
selections= 6C3 * 6*5*4*3
Probability = Selections/ Total_Outcome