Wednesday 22 July 2015

Hauts: Chess With A Twist

Chess With A Twist


Question 1.

Consider a chessboard of dimensions 4xN. What is the value of N among the following such that, you can start with a knight(horse) at some square of the board, proceed by valid moves, visit each square exactly once and can return to the starting point as the 4N+1st square? [Note: If the knight is at a position as shown ­figure, a valid knight move would be any square marked ‘X’] 

(A) 2
(B) 4
(C) 8 
(D) no such N exists 


Question 2.
Consider a chessboard of dimensions 4xN. What is the value of N among the following such that, you can start with a knight(horse) at some square of the board, proceed by valid moves, and can visit each square exactly once, with no requirement that we ever return to the starting square?

(A) 2
(B) 4
(C) 8 
(D) no such N exists 


Question 3.
Find out the minimum number of moves required to move from the situation in the left to that in the right if the valid moves for bishop, rook, knight, king and pawn are shown in the ­gures below respectively.


(A) 9 
(B) 18 
(C) 16 
(D) 8

So, what are you waiting for!! Go ahead & comment your solutions.

20 comments:

  1. Question 1 was a trick question.. Even if you managed to visit all the squares and come back to the original square, it will be your 4Nth square and not (4N+1)th square.

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    Replies
    1. Sorry but that was not we meant. The square you started with was first square. Accordingly, after traveling through all of the other squares, you must return to the initial square as your 4N+1st square

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  2. solution of ques 3

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    1. Answer is (B)18

      Let the squares be a1, a2, a3, b1, b2, b3

      This is the sequence :

      Kb3, a2, Bb2, Na3, Rb1, Ba1, Rb2, Nb1, Ka3, Rb3, Kb2, Na3, Kb1, Bb2, Ka1, Nb1, Ba3, Rb2

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    2. This was one of the easy questions :)

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    3. The answer to question number 3 is (a).
      As this is a logical thinking exam we have to read the question carefully. It did not say that the moves are limited to the six squares. So we can use all the squares in the chess board. Therefore the answer is 9.

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  3. Logically a chess board is a square. Since it is given that dimension of the chess board is 4×N so N must be equal to 4

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  4. This comment has been removed by the author.

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  5. Answer of Q3 should be less than 18 . I don't remember my answer in 10 moves but I have found an answer in 14 moves.
    Let the squares be a1 a2 a3 b1 b2 b3

    Pb3 Bb2 Ka3 Ra2 Ba1 Rb2 Ka2 Pa3 Rb3 Bb2 Ka1 Pa2 Ba3 Rb2

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  6. Answer of Q3 should be less than 18 . I don't remember my answer in 10 moves but I have found an answer in 14 moves.
    Let the squares be a1 a2 a3 b1 b2 b3

    Pb3 Bb2 Ka3 Ra2 Ba1 Rb2 Ka2 Pa3 Rb3 Bb2 Ka1 Pa2 Ba3 Rb2

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    Replies
    1. Firstly, the chess coins should not be moved outside the given part of chessboard.

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    2. They haven't been moved out

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  7. Logically a chess board is a square. Since it is given that dimension of the chess board is 4×N so N must be equal to 4 .therefore ans of ques 1 and 2 must be B.

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  8. the answer to question.3. must be option B. 18

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  9. is the answer of 3 questn '8' ?? after a lot of possibilities 8 min moves are possible

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  10. yep its eight.

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  11. Yaa 8 should be the ans and moreover there is nowhere written in the que that the chess coins cannot move out of the rectangle. So why should we consider the boundation of the rectangle if we want minimum number of moves and even the steps of each coin as given in the question clearly suggests that the rectangle should not be considered. Come on iitians plz think about it before declaring the results or else beauty of the question would go in vain.

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