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# What is the probability of rolling a 7 or 11 when rolling a pair of dice?

I need to know what the probability is.

### 2 Answers by Expert Tutors

Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
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Hi Again Brittany;
When rolling a pair of dice, there are 36 possible arrangements.  We can easily ascertain this by the formula of 62.  Six represents the quantity of options each die offers.  Two represents how many dice we have.

For the probability of seven...
If one die is 6, the other die must be 1.
If one die is 5, the other die must be 2.
If one die is 4, the other die must be 3.
If one die is 3, the other die must be 4.
If one die is 2, the other die must be 5.
If one die is 1, the other die must be 6.

There are six possible scenarios.
So 6/62 = 6/36

For the probability of 11...
If one die is 6, the other die must be 5.
If one die is 5, the other die must be 6.

So 2/62=2/36

We must add the two figures...
6/36 + 2/36=8/36=4/18=2/9

Pran D. | California certified high school teacher in math and physicsCalifornia certified high school teacher...
5.0 5.0 (37 lesson ratings) (37)
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prob of 7 = 6/36
prob of 11 = 2/36
therefore prob of either = 6/36 + 2/36 = 2/9