The first digit of the password can be any of the ten digits - 10 possibilities.
A digit cannot be repeated, so the second digit can be any digit except the one you chose for the first digit - 9 possibilities.
The third digit can be any digit except the digits you chose for the first and second digit - 8 possibilities.
Using the rule of product:

There are 720 passwords.
Answer & Step-by-step explanation:
The formula is given in the middle. You are supposed to insert the value of x into this formula to find the value of y (like in the first given example):

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:Done
Answer: 1/4
Step-by-step explanation:
Since the box box contains four equal-sized cards labeled 1 , 3, 5, and 7. The probability of selecting any number out of the four numbers will be 1/4 if they are selected once.
If Tim selects one card from the box, the probability that Tim will select a card labeled 3 will be: = 1/4
This is because 3 only occurs once and there are 4 numbers in total.