Compute the permutations and combinations.

How many two-digit, positive integers can be formed from the digits 1, 3, 5, and 9, if no digit is repeated?

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12 integers

Step-by-step explanation:

We want two-digit numbers, so let's provide two spaces:

__ __

In the first space, any of the four given numbers (1, 3, 5, and 9) can go there, so we have 4 numbers to choose from for that.

In the second space, because no digit can be repeated, we're only down to 3 possible choices. Think about it this way: if 1 was the first digit, then it can't be the second digit, so we now only have the numbers 3, 5, and 9 to put as the second digit; it's the same situation for any of the 4 numbers you put into the first digit place.

Now, multiply these two:

4 * 3 = 12

There are 12 such numbers.

87%

step-by-step explanation:

apex answer

the olimpics is not going to wokk out

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