The nine digits are arranged in random order to form a nine digit number, using each digit exactly once. Find the probability that 1, 2 and 3 appear as neighbours in the increasing order.
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2 marksStatisticsProbability and Bayes' theoremClassical probability with dice, cards and coinsModerateabout 3 min
DSE 2009 Question 31: Probability and Bayes' theorem
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The nine digits 1,2,…,9 are arranged in random order to form a nine digit number, using each digit exactly once. Find the probability that 1, 2 and 3 appear as neighbours in the increasing order. (A) 1/12 (B) 1/72 (C) 1/84 (D) (2/3)⁹
Also written as: The nine digits 1,2,...,9 are arranged in random order to form a nine digit number, using each digit exactly once. Find the probability that 1, 2 and 3 appear as neighbours in the increasing order.
Probability and Bayes' theorem has come up 190 times in 7 exams since 2004.
What this question tests
This question is on Classical probability with dice, cards and coins, part of Probability and Bayes' theorem in Statistics.
Probabilities of equally likely outcomes found by counting.
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