Question

Two dice are rolled. Find the odds that the score on the dice is either 7 or 12. Am I doing this right?
There are only 3 ways to equal 7 on two dice 6+1,5+2,4+3 so there is a 3/12 chance that I roll a 7 and a 1/12 chance of rolling a 12. my chances of rolling the sum of 7 or 12 is 4/12 but this is where I am stuck. Please help how do I find the odds

Answer 1

I think you need to consider that there is Dice A and Dice B, so your ways to achieve a sum of 7 should be:

1+6
2+5
3+4
4+3
5+2
6+1

(because it matters which diced rolled what number) *There are six numbers on each dice, so the total possibilities should be 6x6=36

SO, for achieving a sum of 7, the total possibility is 6/36 = 1/6

the odds that the score on the dice is "either 7 or 12", means you have to add the two fractions: 1/36 + 6/36 = 7/36

7/36 is the answer.

:)

Answer 2

Yes that does make sense I don't know why I was thinking 12 but 7/36 is not one of the answers in my multiple choice. I believe that 7/36 would be the probability. Do you know how I would get the odds of this happening for this?

Answer 3

odds and probability are not quite the same
the odds in favour of some event
= (the prob of that even will happen):(prob that the event will NOT happen)
so prob of 7 or 12 = 7/36
so prob of not a 7 or 12 is 29/36

so the odd of getting a 7 or 12 is 7:29

(if the odds of some event is a:b, then the prob of that event is a/(a+b) )