Question

Please help please please

Answer 1

First let's have a look:
- nine "consists of":
9=1+8 - impossible (there is no 8, on a dice)
9=2+7 - impossible (there is no 7, on a dice)
9=3+6
9=4+5
9=5+4
9=6+3
9=7+2 - impossible (there is no 7, on a dice)
9=8+1 - impossible (there is no 8, on a dice)

 

the PROPER solution:

Ω - is a set of possible throwing results with two dice:
We have 6 possible outcomes in each throw, so:

|Ω|=6*6=36

A -- a set of these throw results (with two dice), that the sum of the meshes is equal to 9.
We list all possibilities: (3; 6), (4; 5), (5; 4), (6; 3).

So there are 4 options,
that means: |A| = 4

therefore:

               |A|        4
P(A) = --------- = -----
               | Ω |      36

 

 It is 0% of the probability that the first number will be 2, because, as listed before the second number should be 7 (2+7)=9, and there is NO 7 on a dice.