Difficulty: Easy
Correct Answer: 1111110
Explanation:
Introduction / Context:
Binary Coded Decimal (BCD) encodes each decimal digit separately using 4 bits. To obtain a pure binary number, first interpret the BCD as a standard decimal value, then convert that decimal to base-2. This question strengthens fluency with both codings.
Given Data / Assumptions:
Concept / Approach:
Step 1: Decode BCD to decimal by reading each 4-bit group as a digit. Step 2: Convert the resulting decimal number to binary using place values or division by 2. For 126, determine the combination of powers of two that sums to 126.
Step-by-Step Solution:
Decode BCD: 0001 0010 0110 → 1 2 6 → decimal 126.Find nearest powers of two: 64, 32, 16, 8, 4, 2, 1.Express 126 = 64 + 32 + 16 + 8 + 4 + 2.Write ones for used powers and zeros otherwise: 1111110 (bit weights 64 32 16 8 4 2 1).
Verification / Alternative check:
Convert 1111110 back to decimal: 64 + 32 + 16 + 8 + 4 + 2 = 126, matching the original decimal value obtained from BCD.
Why Other Options Are Wrong:
Common Pitfalls:
Treating the entire 12-bit BCD as one binary number directly, or misreading a 4-bit BCD group like 0110 as decimal 6 but then re-encoding incorrectly.
Final Answer:
1111110
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