Given the Boolean expression (A ⊕ B) ∧ (B → C), which of the following rows in…

2025

Given the Boolean expression (A ⊕ B) ∧ (B → C), which of the following rows in the truth table would have an output of 1 (True)?

Answer: A. A = 1, B = 0, C = 1Concept: An exclusive-OR X ⊕ Y is 1 exactly when its two operands hold different truth values, and 0 whenever they agree. An implication X → Y is false in one…

  1. A.

    A = 1, B = 0, C = 1

  2. B.

    A = 0, B = 0, C = 0

  3. C.

    A = 1, B = 1, C = 1

  4. D.

    A = 0, B = 1, C = 0

Attempted by 1 students.

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Correct answer: A

Concept: An exclusive-OR X ⊕ Y is 1 exactly when its two operands hold different truth values, and 0 whenever they agree. An implication X → Y is false in one situation alone — a true antecedent with a false consequent (X = 1, Y = 0) — and is 1 in every other situation, so any row with X = 0 makes it 1. A conjunction P ∧ Q is 1 when P and Q are both 1, and 0 otherwise.

Application: The given expression is a conjunction of A ⊕ B and B → C, so both parts must come out 1 at the same time. Testing the row A = 1, B = 0, C = 1:

  1. A = 1 and B = 0 hold different truth values, so A ⊕ B = 1.

  2. B = 0 makes the antecedent of B → C false, so B → C = 1 whatever C may be; here C = 1.

  3. Both parts are 1, so (A ⊕ B) ∧ (B → C) = 1 ∧ 1 = 1.

The row A = 1, B = 0, C = 1 therefore produces an output of 1 (True).

Cross-check: evaluating each of the four given rows part by part.

Row

A ⊕ B

B → C

Output

A = 0, B = 0, C = 0

0

1

0

A = 0, B = 1, C = 0

1

0

0

A = 1, B = 1, C = 1

0

1

0

A = 1, B = 0, C = 1

1

1

1

Contrast:

  • Across the complete eight-row truth table three assignments give an output of 1 — (A, B, C) = (1, 0, 0), (1, 0, 1) and (0, 1, 1) — but of these, just A = 1, B = 0, C = 1 is offered among the rows listed here.

  • Common pitfall: treating ⊕ as an ordinary OR. An OR would let A = 1, B = 1, C = 1 give an output of 1 as well, whereas exclusive-OR is 0 whenever A and B agree — that is precisely what separates those two rows.

Explore the full course: Gate Guidance By Sanchit Sir

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