Question

The number of 6 digits numbers that can be formed from the digits 1,2,3,4,5,6,&7 so that digits do not repeat and the terminal digits are even is :

Answer 1

If $1$ select & even digit as terminal digit, $1$ can choose the remaining $5$ numbers out of $6$ in $6$ ways & arrange them in $5!$ ways i.e., $-120$ ways. Therefore, when even terminal digit I have $6\times 120=720$. Therefore, for $3$ even terminal digits I have $3\times 720=2160$.