A passcode to enter a building is a sequence of 4 single digit numbers (0−9), and repeated digits aren't allowed.Suppose someone doesn't know the passcode and randomly guesses a sequence of 4 digits.What is the probability that they guess the correct sequence?Choose 1 answer:(A) 10P41(B) 10C41(C) 10P44P4(D) 10P4(4P2)⋅(4P2)
Q. A passcode to enter a building is a sequence of 4 single digit numbers (0−9), and repeated digits aren't allowed.Suppose someone doesn't know the passcode and randomly guesses a sequence of 4 digits.What is the probability that they guess the correct sequence?Choose 1 answer:(A) 10P41(B) 10C41(C) 10P44P4(D) 10P4(4P2)⋅(4P2)
Understand the problem: Understand the problem.We need to calculate the probability of guessing a correct sequence of 4 digits where no digit repeats and each digit can be from 0 to 9.
Calculate total sequences: Calculate the total number of possible 4-digit sequences without repetition.Since the first digit can be any of the 10 digits (0−9), the second digit can be any of the remaining 9 digits, the third can be any of the remaining 8 digits, and the fourth can be any of the remaining 7 digits, we use the permutation formula for this.Total number of sequences = 10×9×8×7=5040This is also denoted as 10P4, which is the number of permutations of 10 items taken 4 at a time.
Calculate probability: Calculate the probability of guessing the correct sequence.Since there is only one correct sequence, the probability of guessing it correctly is 1 divided by the total number of possible sequences.Probability = 10P41=50401
Match with options: Match the calculated probability with the given options.The calculated probability matches option (A), which is 10P41.
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