How many squares are there on a chess board? P.S. No, the answer is not 64 Explanation: Of course, as you might think, aren’t there only 8 x 8 = 64 squares on a chess board? Well, no. All these 64 squares are squares of 1 block. However, one can notice that there are squares of 4 blocks too i.e., 7 x 7 = 49. Likewise, until the largest square which is the chess board … [Read more...] about Permutation Combination – chess board

# GRE Permutation Combination

## Permutation Rearrangement

8 directors, the vice chairman and the chairman are to be seated around a circular table. If the chairman should sit between a director and the vice chairman, in how many ways can they be seated? Answer: 8! * 2 Explanation: Let us consider the vice chairman and the chairman together as one entity. Hence, 8 directors + this entity can be arranged circularly in (9-1)! ways. … [Read more...] about Permutation Rearrangement

## Numerical Entry – Permutations and Combinations

A manager is forming a 6-person team to work on a certain project. From the 11 candidates available for the team, the manager has already chosen 3 to be on the team. In selecting the other 3 team members, how many different combinations of 3 of the remaining candidates does the manager have to choose from? Answer: 56 Explanation The manager has to form a 6-person … [Read more...] about Numerical Entry – Permutations and Combinations