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Non-verbal Reasoning · Question 29 of 65

A square sheet is folded twice as the figure shows, and two holes are punched through the folded paper.

Question 29

HardOriginal question

A square sheet is folded twice as the figure shows, and two holes are punched through the folded paper. Which figure is the sheet when opened?

A square sheet, thought of as a 4 by 4 grid: the left half is folded over onto the right half, then the top half is folded down onto the bottom half. 2 holes are then punched through the folded sheet, in the squares at (row, column) (3, 3), (4, 4) of the original sheet.
Options for question 29

Show the answer and explanation
CorrectNot quiteAnswer C

Correct answer: C

Explanation

  1. Open the folds in reverse order. Opening a fold adds the mirror image of every hole across that fold line, because each hole went through both layers.

  2. Opening step 2 (the horizontal fold) gives holes at (1, 4), (2, 3), (3, 3), (4, 4) (row, column).

  3. Opening step 1 (the vertical fold) gives holes at (1, 1), (1, 4), (2, 2), (2, 3), (3, 2), (3, 3), (4, 1), (4, 4) (row, column).

  4. Figure 3 shows these 8 holes.

Worth noting

The folded sheet has 4 layers, so each punch makes 4 holes. A figure with fewer holes has left a fold closed; one with the right number in the wrong places has opened a fold about the wrong line.

Concept
Unfolding a punched sheet: reflect the holes across each fold line
Typical time
110 s
Your time
—
The rule this testsPaper folding and punching
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