The total number of 5-digit numbers that can be composed of...

Number of 5 digits numbers with all distinct digit is same as filling of 5 vacent placed out of 10 boxes. First digit of any number can be choosen in 9 ways. Remaining 4 digits can be choosen in remaining 9 digits in ${ }^9 \mathrm{P}_4$ ways. Total number of such number $=9 \times 9 \times 8 \times 7 \times 6=27216$