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Soni-kay
Al locker combination uses three digits, without repetition, of the digits 0-9. What is the probability that Chris will choose the correct combination on his first attempt to open the locker?
as we choose the first number, we have 10 options, since we cant repeat, the second number has 9 options and the third has 8 options 10*9*8 possible combinations so if he chooses completely at random we have 1/(10*9*8)