ISRO Computer Science (CSE) 2025 - Question 52

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Topic: Digital Logic

The given Boolean expression is:
$X^{\prime}Y^{\prime}Z^{\prime}+X^{\prime}YZ^{\prime}$
Which of the following represents the Karnaugh map for the above expression?

  • A. Option showing 1s at X'Y'Z' and X'YZ' in a 4-row (X'Y', X'Y, XY, XY'), 2-column (Z', Z) format
  • B. Option showing 1s at X'Y'Z and X'YZ in a 4-row format
  • C. Option showing 1s in a 2-row format that do not match the expression
  • D. Option showing 1s in a 2-row format that do not match the expression

Answer: A. Option showing 1s at X'Y'Z' and X'YZ' in a 4-row (X'Y', X'Y, XY, XY'), 2-column (Z', Z) format

Explanation: The given expression has two minterms: $X'Y'Z'$ and $X'YZ'$. In a Karnaugh map with rows representing XY combinations and columns representing Z combinations, we need 1s located precisely at the cell for $X'Y'$ row under $Z'$ column, and the cell for $X'Y$ row under $Z'$ column. Option (a) accurately reflects this placement.

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