Answer:
72
Explanation:
For a five-digit number to be odd it's one digit must be 1,3,5.
So there can be no repeats of any digits.
Let's look at numbers with one's digit being 1.
There are 4 ways to choose the tabs digit.
After that you can choose the hundreds digit 3 ways.
The thousands digit can then be chosen 2 ways.
Then finally the ten-thousands digit can be chosen 1 way.
4×3×2×1=24
24 odd numbers with one's digit being 1 that are 5 digits long only using 1,2,3,4, and 5 with no repeats.
That means there are 24 odd numbers with one's digit being 3 that are 5 digits long only using 1,2,3,4, and 5 with no repeats.
Also means there are 24 odd numbers with one's digit being 5 that are 5 digits long only using 1,2,3,4, and 5 with no repeats.
3(24)=72