Mixed-base identity check: “12 (decimal) = 1101 (binary) = C (hexadecimal) = 0001 0010 (BCD).” Determine whether this chain of equalities is valid.
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AIncorrect
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BCorrect
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CCorrect only if parity is even
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DCorrect after rounding
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ECorrect except for the BCD part
Answer
Correct Answer: Incorrect
Explanation
Introduction / Context:Verifying equivalence across bases is a common skill in digital fundamentals. This item intentionally mixes correct and incorrect conversions to test careful checking of each representation: binary, hexadecimal, and packed BCD for the same decimal value 12.
Given Data / Assumptions:
- Target value: 12 decimal.
- Binary conversion must reflect base-2 positional weights.
- Hexadecimal C corresponds to 12 decimal.
- Packed BCD encodes each decimal digit in 4 bits.
Concept / Approach:Evaluate each equality independently. Decimal 12 in binary is 1100 (8+4+0+0), not 1101 (which equals 13). Hexadecimal C equals 12, which is correct. Packed BCD for 12 is 0001 0010 (digit “1” → 0001; digit “2” → 0010), which is also correct. Therefore, because the binary term is wrong, the full chain is not valid.
Step-by-Step Solution:
Compute 12 in binary: 12 = 8 + 4 = 1100.Check given binary 1101: 8 + 4 + 1 = 13 → mismatch.Confirm hex: C = 12 → correct.Confirm BCD: 12 → 0001 0010 → correct.Verification / Alternative check:Convert the allegedly equal 1101 back to decimal: 18 + 14 + 02 + 11 = 13. Since this differs from 12, the chain fails. Two correct items (hex and BCD) cannot fix one wrong item (binary).
Why Other Options Are Wrong:
- Correct: Would require all representations to match 12; they do not.
- Correct only if parity/rounding: Parity and rounding are irrelevant to base conversion.
- Correct except for BCD: BCD part is actually correct; the binary is not.
Common Pitfalls:Mistaking 1101 for 12 due to visual similarity; forgetting that BCD encodes decimal digits, not values directly; neglecting to recheck each piece independently.
Final Answer:Incorrect