Home » Aptitude » Permutation and Combination

In how many different ways can four books A, B, C and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?

Correct Answer: 12

Explanation:

The number of arrangement in which A and B are not together
= Total number of arrangement - Number of arrangement in which A and B are together
= 4! - 3! x 2! = 24 - 12 = 12

← Previous Question Next Question→

More Questions from Permutation and Combination

Boxes numbered 1, 2, 3, 4 and 5 are kept in a row and they are to be filled with either a red or a blue ball such that no two adjacent boxes can be filled with blue balls Then, how different arrangements are possible, given that all balls of a given colour are exactly identical in all respects?
A child has four pockets and three marbles. In how many ways, the child can put the marbles in the pockets?
In how many ways, can the letters of the word 'ASSASSINATION' be arranged, so that all the S are together?
Find the number of ways, in which 12 different beads can be arranged to form a necklace .
20 persons were invited to a party. In how many ways, they and the host can be seated at a circular table?
In how many different ways, 5 boys and 5 girls can sit on a circular table, so that the boys and girls are alternate?
How many necklaces of 12 beads can be made from 18 beads of various colours?
In how many ways, a committee of 3 men and 2 women can be formed out of a total of 4 men and 4 women?
In how many ways, a cricket team of 11 players can be made from 15 players, if a particulars player is always chosen?
There is a polygon of 12 sides . How many triangles can be drawn using the vertices of polygon?

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion