Question

An ordinary (fair) die is a cube with the numbers 1 through 6 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 8 .
Event : The sum is an even number.

Answer 1

b) is it 1/2

Answer 2

a) is it 5/18

Answer 3

a) the sum is greater than 8
combinations possible are
3,6
4,6
5,6
6,6
4,5
5,5
the occurance of 3,6 is (1/6)*(1/6) which is 1/36
likewise all the remaining 5 cases have probability 1/36
totally there are six cases so it should be 6*(1/36) so the probability of having sum greater than 8 is 1/6
is the ans correct??

Answer 4

wait so for the first answer is it 1/6 or 5/18?

Answer 5

a) {(6,3)(3,6),(4,5)(5,4),(5,5),(6,4)(4,6),(6,5),(5,6),(6,6)}

Answer 6

@matricked dude you are right

Answer 7

i didnt consider those cases

Answer 8

b) for 1/2 the sum will be odd and other half will be even