7. Consider the sequence 1, $, 2, 16, 20 a) List the next two terms of the sequence. Enter fractions with slashes (ex. 1/2). b) Assuming the sequence is denoted by A1, A2, A3 . . . give an explicit formula for AN. AN = 8. Airlines would like to board passengers in the order of decreasing seat numbers (large seat number first, second largest next, and so on), but passengers don't like this policy and refused to go along. If two passengers randomly board a plane but probability that they board in order of decreasing some seat numbers is 1/2; If three passengers randomly board the plane the probability that they board in order of decreasing seat number is 1/6 ; If four passengers randomly board a plane the probability that they board in order of decreasing seat number is 1/24; and if five passengers randomly board a plane, the probability they board in order of decreasing seat number is 1/120. Use the sequence 1/2, 1/6, 1/24, 1/120, ... as your guide, a) Determine the probability that if six passengers randomly board a plane they board in order of decreasing seat numbers. Enter your answer as a fraction. b) Determine the probability that if 12 passengers randomly board a plane, they board in order of decreasing seat numbers. Enter your answer as a fraction. not UO on 9. When two fair coins are tossed the probability of tossing 2 heads is 1/ 4; When 3 fair coins are tossed the probability of tossing 2 heads and one tail is 3 / 8; when four fair coins are tossed the probability of tossing 2 heads and two tails is 6 out of 16; When 5 fair coins are tossed the probability guide of tossing 2 heads and three tails is 10 out of 32. Using the sequence 1/4, 3/8, 6/16, 10/32, ... as your a) Determine the probability of tossing 2 heads and 4 tails when 6 fair coins are tossed. 1 b) Determine the probability of tossing 2 heads and 10 tails when 12 fair coins are tossed. (Hint: find the explicit formula first.)