GATE CS 2024 Set 2 — Question 10

MCQ+2 / -0.67MediumNumerical Relations & ReasoningAnalytical AptitudeGeneral Aptitude

General Aptitude → Analytical Aptitude → Numerical Relations & Reasoning

Last updated

Question

In the 4×44 \times 4 array shown below, each cell of the first three rows has either a cross (X) or a number.
4x4 grid with numbers and crosses
The number in a cell represents the count of the immediate neighboring cells (left, right, top, bottom, diagonals) NOT having a cross (X). Given that the last row has no crosses (X), the sum of the four numbers to be filled in the last row is
A.
11
B.
10
C.
12
D.
9

Correct answer

(A) 11

Solution

Let the cells in the last row (Row 4) be denoted as C4,1,C4,2,C4,3,C4,4C_{4,1}, C_{4,2}, C_{4,3}, C_{4,4}. We are given that the last row has no crosses, so all cells in Row 4 contain numbers. A number in a cell represents the count of neighbors (horizontal, vertical, diagonal) that do not contain 'X'.
Grid Context:
Row 3: 3,X,6,X3, X, 6, X
Row 4: C4,1,C4,2,C4,3,C4,4C_{4,1}, C_{4,2}, C_{4,3}, C_{4,4} (All are numbers, i.e., not X)
Calculating C4,1C_{4,1} (Corner):
Neighbors: (3,1)=3(3,1)=3 (Not X), (3,2)=X(3,2)=X, (4,2)(4,2) (Not X).
Count of non-X neighbors = 2.
C4,1=2C_{4,1} = 2Calculating C4,2C_{4,2} (Edge):
Neighbors: (4,1)(4,1) (Not X), (3,1)=3(3,1)=3 (Not X), (3,2)=X(3,2)=X, (3,3)=6(3,3)=6 (Not X), (4,3)(4,3) (Not X).
Count of non-X neighbors = 4.
C4,2=4C_{4,2} = 4Calculating C4,3C_{4,3} (Edge):
Neighbors: (4,2)(4,2) (Not X), (3,2)=X(3,2)=X, (3,3)=6(3,3)=6 (Not X), (3,4)=X(3,4)=X, (4,4)(4,4) (Not X).
Count of non-X neighbors = 3.
C4,3=3C_{4,3} = 3Calculating C4,4C_{4,4} (Corner):
Neighbors: (4,3)(4,3) (Not X), (3,3)=6(3,3)=6 (Not X), (3,4)=X(3,4)=X.
Count of non-X neighbors = 2.
C4,4=2C_{4,4} = 2Sum:
Sum = 2+4+3+2=112 + 4 + 3 + 2 = 11.

More questions on Analytical Aptitude

Practice GATE CS PYQs with adaptive difficulty

Timed practice, skill tracking, and AI explanations — free to start.

Start practicing free