HEREDITY
BASICS OF PROBABILITY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A 4 digit PIN is selected. What is the probability that there are no repeated digits?
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5, 047
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3, 042
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15, 120
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720
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Explanation:
Detailed explanation-1: -Hence, total number of four digit numbers, without repetitions, which are divisible by 5 are 504+448=952.
Detailed explanation-2: -To have no repeated digits, all four digits would have to be different, which is selecting without replacement. We could either compute 10 · 9 · 8 · 7, or notice that this is the same as the permutation 10P4 = 5040. Hence, there is a 50.4% chance that the 4-digit PIN has no repeated digits.
Detailed explanation-3: -Hence total number of permutations = 9×504=4536.
There is 1 question to complete.