Question

Five different books (A, B, C, D and E) are to be arranged on a shelf. Books C and D are to be arranged first and second starting from the right of the shelf. The number of different orders in which books A, B and E may be arranged is
1. 5!
2. 3!
3. 2!
4. 4!

Answer 1

Correct Answer - Option 2 : 3!

Books C and D are arranged first and second starting from the right side of the shelf.

Thus only three books are remaining i.e. A, B, and E.

The number of different orders in which books A, B, and E may be arranged is 3!

3! = 3 × 2 × 1 = 6 ways

For example, If we arrange book A third, fourth and fifth from the right then book B can arrange only on 2 positions, and book E can arrange on a single position

Hence, the correct answer is 3!.