Thread: PROBABILITY problems help please

1) A five-digit number is created using the digits 1-5 each once. What is the probability that the number is odd? 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:



As Plato pointed out, I made a mistake and overlooked your problem said, 'each digit appears once'. Instead of deleting it, let's just say this is the case where the digits repeat.

Originally Posted by sri340

1) A five-digit number is created using the digits 1-5 each once. What is the probability that the number is odd? 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?

Originally Posted by galactus

#1:

That answer is for numbers with repeated digits.
The problem says "each once".
Try

#2 hint If the sum of the digits is multiple of three the the number is divisiable by three.

Oh, I overlooked that.

Thanks.