P(at least 5 rolls until 1) = P(4 rolls are not 1) = 5/6 x 5/6 x 5/6 x 5/6 = 0.4823 (4sf)
Fewer than 7 rolls to get second 1 after first takes 3 rolls means second occurs on 4th, 5th or 6th roll
The probability of each of these is 1/6, 5/6 x 1/6 and 5/6 x 5/6 x 1/6 respectively.
P(second 1 on 4th, 5th or 6th roll) = 1/6 + 5/36 + 25/216 = 91/216 = 0.4213 (4sf)
Step-by-step explanation:
The given scenario falls under the category of conditional probability. There are a total of 56 people in the fishing group described above. The probability that the a person caught a fish and fished from a boat is 24/56. The probability that he fished from a boat is (24+11)/56. For the conditional probability in this item is,
P = (24/56) / ((24+11)/56) = 24/35 = 0.69
