1.AN ORDINARY CUBE HAS FOUR BLANK FACES,ONE FACE MARKED 2 ANOTHER MARKED 3.THEN THE PROBABILITY OF OBTAINING A TOTAL OF EXACTLY 12 IN 5 THROWS?

2.IN A CLASS OF 125 STUDENTS 70 PASSES IN MATHEMATICS,55 IN STATISTICS AND 30 IN BOTH.THE PROBABILITY THAT A STUDENT SELECTED AT RANDOM FROM THE CLASSES,HAS PASSED IN ONLY ONE SUBJECT IS        A)13/25                           B)3/25

                          C)17/25                            D)8/25

 

PLEASE TELL ME THE SOLUTION SIR.

Dear debajeet

 

We (experts) are asked to not answer queries related to multiple questions in a single post. So next time pls take care to send just one at a time.

Here i consider only first query to be answered.

 

Total sum of 15 in 5 throws is only possible if all the 5 time we obtain 3.

 

So probalility of occurence of 3 = 1/6

 

So probability of occurence of 3 in all the 5 trials = (1/6)⁵

 

This gives probability of sum to be 15 in 5 throws = (1/6)⁵