GATE CS 2026 Set 2 Q.9: Analytical and Logical Reasoning

The figure in Panel I below is a grid of cells with four rows and four columns. The numbers on the top and on the left represent the number of cells that are to be shaded in that column and row, respectively. Which one of the options shown in Panel II below represents the grid shaded correctly?

Panel I: an empty 4 by 4 grid with column counts 2, 2, 2, 2 on top and row counts 3, 1, 2, 2 on the left. Panel II: four candidate 4 by 4 grids (i), (ii), (iii) and (iv) with some cells shaded grey.

(i)

(ii)

(iii)

(iv)

Official answer and solution

Official answer: B
From: Official GATE 2026 answer key

Solution

Check the row sums $(3, 1, 2, 2)$ and column sums $(2, 2, 2, 2)$ of each candidate grid in Panel II.

We require row counts $(3, 1, 2, 2)$ from top to bottom and column counts $(2, 2, 2, 2)$ from left to right:

In (i): Row 2 has 2 shaded cells (violates row 2 count of 1) and Row 3 has 1 shaded cell.
In (ii): Row counts are $3, 1, 2, 2$ and column counts are $2, 2, 2, 2$ . Every constraint is satisfied.
In (iii): Row 2 has 2 shaded cells and Column 3 has 3 shaded cells.
In (iv): Row 3 has 1 shaded cell and Row 4 has 3 shaded cells.

Hence (ii) is the only valid grid.

Final answer

Option (B)

Common trap

Checking only the column sums of (iv) without checking its row 3 and row 4 counts.

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

Source

Paper: GATE 2026 Computer Science and Information Technology - Session 2 (CS2)
Question: 9 of 65
Section: General Aptitude

Report an error in this question

GATE questions are the work of the organising institutes. This site is independent and is not affiliated with them.

Question

Solution

Source