From the set: S= {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, how many 9-digit permutations are there, where 5 digits are even and 4 digits are odd in any order? Thank you.
If the first digit is even, then we have: (4* 5^8) * (8 C 4)= 109,375,000
If the first digit is odd, then we have: (5^9)* (8 C 3)=109,375,000
Total ==109,375,000 + 109,375,000 ==218,750,000 such permutations
