Doubt regarding choice of formula...

Asked by RACHIT_MAHAAN | 21st Mar, 2012, 12:56: PM

Expert Answer:

Both the techniques are correct , we can help u by giving an example ,
Lets say u have to calculate probability of an event where a dice is tossed thrice , number 6 appears only once .
 
The above problem can have sample spaces { 6 , not 6 , not 6 } , {not 6 , 6 , not 6} , {not 6 , not 6 , 6}
So probability =  3 * 1/6 * 5/6 * 5/6
But we can also say that out of the three probabilities 2 are same 5/6
So answer can be
1/6 * 5/6 * 5/6 * 3C2

Answered by  | 22nd Mar, 2012, 02:56: PM

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