GATE Mechanical 2023 | GA | Question: 5

Question

The symbols $\bigcirc, \ast , \bigtriangleup$, and $\square$ are to be filled, one in each box, as shown below.

The rules for filling in the four symbols are as follows.

1. Every row and every column must contain each of the four symbols.
2. Every $2 \times 2$ square delineated by bold lines must contain each of the four symbols.

Which symbol will occupy the box marked with '?' in the partially filled figure?

• A. $\bigcirc$
• B. $\ast$
• C. $\bigtriangleup$
• D. $\square$

Comments

basically a $4\times4$ sudoku

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Moreover, it is similar to a group theory question.

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Simple Just like a Sudoku Game 

Answer 1

Answer: (B) -(*)

Last row have one missing i.e Square

Then 1x2 will not contain square, circle and triangle (as row already contain triangle)

so only * remains

Answer 2

Given that, the rules for filling in the four symbols are as follows.

1. Every row and every column must contain each of the four symbols.
2. Every $2 \times 2$ square delineated by bold lines must contain each of the four symbols.

That means each row and each column in the grid must contain different symbols. In other words, no symbol can be repeated within the same row or the same column.

We have four symbols: $\bigcirc, \ast , \bigtriangleup$, and $\square$

We can easily fill it from the bottom.

Correct Answer: B

Comments

simple sudoku

ans-b