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A combination lock on a suitcase has 3 wheels, each labelled with nine digits from 1 to 9. If an opening combination is a particular sequence of three digits with no repeats, what is the probability of a person guessing the right combination ?

User Jpwatts
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Final answer:

The probability of guessing the right combination for a 3-wheel suitcase lock with no repeats is 1/504, calculated by multiplying the possible choices for each wheel and then taking the inverse.

Step-by-step explanation:

To calculate the probability of guessing the right combination on a suitcase lock with 3 wheels and 9 digits (1-9) with no repeats, we must find the number of possible unique combinations. Since the first digit can be any of the 9 digits, for the second digit we have 8 choices left (as repeats are not allowed), and for the third digit, we have 7 choices left. The total number of unique combinations is the product of these choices, which is 9 × 8 × 7.

So, the number of combinations is 9 × 8 × 7 = 504. The probability of guessing the correct combination is 1 divided by the number of possible combinations. Therefore, the probability is 1/504, which is the answer to this probability problem.

User Pyrocrasty
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