probability help

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 A

: The sum is greater than 8

.

Event B

: The sum is an odd number.

Round your answers to two decimal places.

Answer 1

The sums (2,3,4,5,6,7,8,9,10,11,12) have the probabilities (1,2,3,4,5,6,5,4,3,2,1)/36 (easy to remember pattern, but you can count out the number of ways of getting a sum/6² possible sums).

P(sum>8) = P(9) + P(10) + P(11) + P(12) = (4+3+2+1)/36 = 5/18

P(sum is odd) = P(3) + P(5) +...

I'll leave the second one to you.

Please consider a tutor. Take care.