Use our 2 dice calculator, you have 2 ways to roll an 11 (5, 6) --> P(5, 6) = 1/36 (6, 5)--> P(6, 5) = 1/36 We want P(5, 6) + P(6, 5): P(5, 6) + P(6, 5) = 1/36 + 1/36 P(5, 6) + P(6, 5) = 2/36 P(5, 6) + P(6, 5) = 1/18