Question

Four-digit numbers are to be formed using the digits 1, 2, 3 and 4; and none of these four digits are repeated in any manner.

Further,

1. 2 and 3 are not to immediately follow each other

2. 1 is not be immediately followed by 3

3. 4 is not to appear at the last place

4. 1 is not to appear at the first place

How many different numbers can be formed?

1. 6
2. 8
3. 9
4. None of the above

Answer 1

Correct Answer - Option 1 : 6

Case I : When 1 is at last pace..
There are two arrangements possible : 3 4 2 1, 2 4 3 1

Case II : When 2 is at last place.
There are three arrangements possible : 3 1 4 2, 3 4 1 2, 4 3 1 2

Case III : When 3 is at last place.
There is only one arrangement possible : 2 1 4 3

Therefore, total 6 different numbers are formed.
Hence, option 1 is the correct answer.