Find the probability for the experiment of tossing a six-sided die twice.

Question

The sum is 5, 10, or 11.

Answer 1

First throw numbers along the top and 2nd throw numbers along the side with sums in the middle:

1 2 3 4 5 6

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1 | 2 3 4 5 6 7

|

2 | 3 4 5 6 7 8

|

3 | 4 5 6 7 8 9

|

4 | 5 6 7 8 9 10

|

5 | 6 7 8 9 10 11

|

6 | 7 8 9 10 11 12

There are 4 ways to get the number 5. there are 3 ways to get the number 10, and there are 2 ways to get the number 11. That adds up to 9 ways to get either the numbers five, ten, or eleven.

There are 36 total possibilities. So the probability is 9/36 or 1/4