problem

Question

problem

anonymous · Answer

@satellite73

anonymous · Answer

@DanielxAK

anonymous · Answer

given that one die shows 3, the only probability you have to worry about is getting a 5 on the second dice, which is a 1/6 chance

anonymous · Answer

I had a different problem that asked about getting exactly 3 on one and that was what I did, but this is different, since it says "at least"

I'm just not sure how it's different

anonymous · Answer

Oh ic, so there are two possible outcomes:

anonymous · Answer

on the first roll you could do the 3, then on the second roll you would need a 5. Or on the first roll you could roll something, then on the second roll a 3.

anonymous · Answer

would it be (2/5)*(5/36)??

anonymous · Answer

where does your 2/5 come from?

anonymous · Answer

2 from 2 ways to get 8 when one die is  3... (3,5) and (5,3)
5 from all the ways to get 8...(2,6)(6,2)(4,4)(3,5)(5,3)

anonymous · Answer

ahh it's not right!

anonymous · Answer

In this case we are only concerned about the probabilities of getting 8 from 3 and 5

anonymous · Answer

so if 3 is given on the first roll, then we only calculate the probability of the second roll: 1/6 is a 5 and 5/6 are not a 5.

anonymous · Answer

What would I do from there?

anonymous · Answer

no, thats wrong its still a 1/6 probability on the second roll

anonymous · Answer

Jon was right. It's 1/6. If you want to see it visually, make a table:

   1 2 3 4 5 6
_________________
1 | 3 4 5 6 7
2 | 4 5 6 7 8
3 | 5 6 7 8 9
4 | 6 7 8 9 10 
5 | 7 8 9 10 11
6 | 8 9 10 11 12

Note: You know that one of the die is three. It doesn't matter which one. So, look at everything below the row at 3. How many ways are there to get 8? 3. How many choices do you have below 3? 18.

So, 3/18 = 1/6.

There's probably a better way to write it in Probability notation, but I'm tired. Sorry. This is a bit more intuitive, though.

anonymous · Answer

I thought that would be if there was exactly one 3? This means I did the first part incorrectly!

What would be the probability if we have exactly one die that shows a 3 instead of "at least"?

anonymous · Answer

If one dice shows a three then, it is still 1/6 chance youll roll a 5 on the next

anonymous · Answer

Exactly one die means the other die cannot be a three. So, if you look at the table again, continue to look at everything below the 3 at the row and take out the column at 3. So, you would have 15 choices, but only 2 possibilities of getting an 8.

anonymous · Answer

sorry something is wrong with my computer!

anonymous · Answer

that was correct though