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Wanted outcomes are 3, 6, 9, 10, 11, 12.
3 = 1+2, or 2+1, ====> so there are 2 ways to get the sum of 3.
6 = 1+5, 2+4, 3+3, 4+2, or 5+1 ====> so there are 5 ways to get the sum of 6.
9 = 6+3, 5+4, 4+5, 3+6 ====> so there are 4 ways to get the sum of 9.
10 = 6+4, 5+5, 4+6 ====> so there are 3 ways to get the sum of 10.
11 = 6+5 and 5+6 ====> so there are 2 ways to get the sum of 11.
12 = 1+1 ====> so there is 1 way to get the sum of 12.
Thus you have 2 + 5 + 4 + 3 + 2 + 1 = 17 wanted cases of 36 possible outcomes.
The probability under the question is
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