Question

A pair of two dice is tossed 2 times. Compute the following. Get a sum of seven at least one time on all both tosses. Write the answer as a decimal number rounded to third place value or as a reduced fraction using "/" as the fraction bar.

Answer 1

Total sample space = 6 * 6 = 36

P(sum of 7) = P(1,6) + P(2,5) + P(3,4) + P(4,3) + P(5,2) + P(6,1) = 6/36 = 1/6

P(at least one time 7) = 1 - P(no 7 on both times)

                                   = 1 - (1 - 1/6)²

                                   = 0.306