Number systems: Convert the binary value 1011011₂ to its decimal (base-10) equivalent. Show the positional weights used.
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A81₁₀
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B91₁₀
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C100₁₀
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D200₁₀
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ENone of the above
Answer
Correct Answer: 91₁₀
Explanation
Introduction / Context:Binary-to-decimal conversion reinforces the idea that each bit position represents a power of two. Practicing the expansion method prepares learners for interpreting register contents and memory addresses.
Given Data / Assumptions:
- Binary input: 1011011₂.
- Bit positions from right (LSB) have weights: 2^0, 2^1, 2^2, ...
- Unsigned magnitude, no sign bit.
Concept / Approach:To convert, multiply each bit by its corresponding power-of-two weight and sum the results. Only positions with bit = 1 contribute to the sum.
Step-by-Step Solution:Write weights for 7 bits (MSB→LSB): 64, 32, 16, 8, 4, 2, 1.Match bits 1 0 1 1 0 1 1 → use weights 64, 16, 8, 2, 1.Compute sum: 64 + 16 + 8 + 2 + 1 = 91.Therefore 1011011₂ = 91₁₀.
Verification / Alternative check:Convert back by repeated division by 2 on 91 to reconstruct 1011011₂; the remainders match the bit pattern.
Why Other Options Are Wrong:81₁₀, 100₁₀, 200₁₀: these sums do not equal the expansion of the given bit pattern.None of the above: incorrect because 91₁₀ is correct.
Common Pitfalls:Misaligning bit weights; forgetting to include both the 2 and 1 contributions at the end.
Final Answer:91₁₀