1) What is the probability that the last three digits of a randomly selected phone number are all prime? Express your answer as a common fraction 2) The sum of the digits of a number is 9. What is the probability that the number is prime?
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Originally Posted by sri340 1) What is the probability that the last three digits of a randomly selected phone number are all prime? Express your answer as a common fraction 2) The sum of the digits of a number is 9. What is the probability that the number is prime? 1) There are four prime digits: . Picking a digit at random there is probability that it is prime. Now you finish. 2) If the sum of the digits is multiple of nine then the number is divisible by nine. What does tell you?
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