SOLUTION: The digits 1,2,3,4 and 5 are randomly arranged to form a 3 digit number. Digits r not repeated. Find probability that the number is even and greater than 500.

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Question 1102947: The digits 1,2,3,4 and 5 are randomly arranged to form a 3 digit number. Digits r not repeated. Find probability that the number is even and greater than 500.
Answer by ikleyn(52802) About Me  (Show Source):
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The total space of events consists of 5*4*3 = 60  3-digit numbers, consisting of non-repeating digits  1, 2, 3, 4 and 5.


Of them, only those that start with 5 and end with 2 or 4 are even greater than 500.


If the last digit is "2", then the second digit is any of 1, 3, and 4  (3 possibilities).


If the last digit is "4", then the second digit is any of 1, 3, and 2  (3 possibilities).


In all, there are 3+3 = 6  of these "eligible" numbers.


The probability under the question is 6%2F60 = 1%2F10.