Problem 10 · 2018 Math Kangaroo
Medium
Logic & Word Problems
gridcasework
Albert places these 5 figures on a 5×5 grid. Each figure is only allowed to appear once in every column and once in every row. Which figure does Albert have to place on the field with the question mark?
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Answer: A
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Hint 1 of 2
Each of the five figures shows up exactly once in every row and exactly once in every column.
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Hint 2 of 2
Look along the question mark's row and down its column, and cross out every figure you already see there.
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Approach: cross out every figure already in the marked cell's row and column; one figure is left
- Because no figure repeats in a row or a column, the missing one must be a figure not yet in that row or column.
- Read across the marked cell's row and down its column and cross off each figure that already appears.
- Exactly one figure is never crossed off, and that is the one that belongs in the question-mark cell, answer A.
Mark:
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