How many 4 digits codes can be formed with odd numbers without repetition? 0 is not allowed.

9514 1404 393

  120

Step-by-step explanation:

The number of permutations of 5 things taken 4 at a time is 120.

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There are 5 odd digits. You want to choose 4 of them, then arrange those 4 in all possible ways. There are 5·4·3·2 = 120 ways to do that.

120 4-digit codes can be formed using odd digits with no repetition.

4 and 5)16.97 or 12√2

6)15.59 or 9√3

7)y = 15.59 or 9√3     x =27

8)17.80