GATE CS 2025 Set 2 Q.4: Spatial Aptitude

The paper as shown in the figure is folded to make a cube where each square corresponds to a particular face of the cube. Which one of the following options correctly represents the cube?

Note: The figures shown are representative.

Unfolded net of a cube consisting of a horizontal row of four squares (blank, hollow upright triangle, blank, solid black upright triangle), with a solid black circle square above the second square and a hollow circle square below the second square.

Cube option (A) with a hollow upright triangle on the front face, a solid black circle on the top face, and a blank right face.

Cube option (B) with a hollow upright triangle on the front face, a blank top face, and a solid black upright triangle on the right face.

Cube option (C) with a hollow upright triangle on the front face, a blank top face, and a blank right face.

Cube option (D) with a hollow upright triangle on the front face, a solid black triangle on the top face, and a solid black circle on the right face.

Official answer and solution

Official answer: A
From: Official GATE 2025 answer key

Solution

Fix the square containing the hollow upright triangle as the front face and determine which faces fold to the top, bottom, left, right, and back.

In all four options, the front face shows the hollow triangle ( $\triangle$ ) upright, matching its orientation in the unfolded net:

Folding the square directly above $\triangle$ backward by $90^\circ$ places the solid black circle ( $\bullet$ ) on the top face.
Folding the square directly to the right of $\triangle$ backward by $90^\circ$ places a blank square on the right face.
The square with the solid black triangle ( $\blacktriangle$ ) folds behind to form the back face (opposite to $\triangle$ ), and the hollow circle ( $\circ$ ) forms the bottom face.

Therefore, when $\triangle$ is upright on the front face, the top face has $\bullet$ and the right face is blank, which matches Option (A).

Final answer

Option (A)

Common trap

Choosing (C) by overlooking that the top face directly above the upright hollow triangle must carry the solid black circle.

The answer is the one in the official GATE answer key. The solution is this site's own explanation.

Source

Paper: GATE 2025 Computer Science and Information Technology - Session 2 (CS2)
Question: 4 of 65
Section: General Aptitude

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