Question:
Total number of 6-digit numbers in which only and all the five digits $1,3,5,7$ and 9 appear, is :
Correct Option: 1
Solution:
Total number of 6-digit numbers in which only and all the five digits $1,3,5,7$ and 9 is
${ }^{5} \mathrm{C}_{1} \times \frac{6 !}{2 !}$