Probabilities in statistcs

Question

An ordinary (fair) die is a cube with the numbers through on the sides (represented by painted spots). Imagine that such a die is rolled twice in succession and that the face values of the two rolls are added together. This sum is recorded as the outcome of a single trial of a random experiment.Compute the probability of each of the following events:

Event : The sum is greater than 9  .
Event : The sum is an odd number.

Answer 1

Hi Adrin,

 

A die is rolled twice, so sample space would be

S= { (1,1)(1,2)(1,3)(1,4)(1,5)(1,6),(2,1)(2,2).....................(6,1)(6,2)...(6,6)}

n(S)= 36

 

Event : The sum is greater than 9 , {(5,5), (5,6) (6,5) (6,6)}

 

P( the sum is greater than 9)= 4/36 = 1/9

 

Event: The sum is an odd number, {(1,2),(1,4),(1,6), (2,1),(2,3), (2,5),(3,2),(3,4),(3,6),(4,1),(4,3),(4,5),(5,2)(5,4),(5,6),(6,1),(6,3),(6,5)}  total 18 fav 

 

P(The sum is an odd no) = 18/36=1/2