Question

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?

Answer 1

5

Explanation:

Answer 2

The number of two-digit, positive integers that can be formed from the digits 1, 3, 5, and 9, if no digit is repeated are:

12

Explanation:

We are asked to find the number of two-digit number that can be formed using the digits:

1,3 ,5 and 9

We know that the number of such digits possible are:

4×3=12

( Since at the first place there are 4 choices as any of the 4 numbers could come at the first place and also at the second place there are a choice of 3 numbers as the digit's can't be repeated )

Hence, the answer is:

12