Question

How many even numbers of 3 different digits
can be formed from the digits 1, 2, 3, 4, 5, 6,
7,8,9 (repetition is not allowed)​

Answer 1

$\huge \fbox{ \mathtt {SOLUTION :)</p><p>}}$

The unit's place can be filled in 4 different ways by anyone of the 2 , 4 , 6 , 8

The ten's palce can be filled in 8 different ways by anyone of the remaining digits

The hundred's place can be filled in 7 different ways by anyone ot the remaining digits

By multiplication principle ,

$\sf \hookrightarrow The \: no. \: of \: 3 \: digit \: even \: no. \: = 4 × 8 × 7 \\ \\ \sf \hookrightarrow </p><p>The \: no. \: of \: 3 \: digit \: even \: no. \: = 224 </p><p>$

Hence , 224 three digit even numbers can be formed by using the 1, 2, 3, 4, 5, 6, 7, 8, 9 digits when repetition is not allowed