Binary to octal — group bits by threes Convert the binary number 010111100 (base 2) into its octal (base 8) representation.
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A1728
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B2728
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C1748
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D2748
Answer
Correct Answer: 2748
Explanation
Introduction / Context:Octal and binary interconvert by grouping binary digits into sets of three, starting from the right. Each 3-bit group corresponds to one octal digit (0–7). This method is fast and avoids arithmetic division when the binary string is already available.
Given Data / Assumptions:
- Binary input: 010111100.
- We may pad the most significant side with zeros to form complete 3-bit groups.
- Octal digits map from 000→0 up to 111→7.
Concept / Approach:
Partition the binary string into 3-bit chunks from right to left, then translate each chunk to its octal digit. Keep the left-to-right order of the resulting octal digits.
Step-by-Step Solution:
Create groups: 010 111 100.Map to octal: 010→2, 111→7, 100→4.Concatenate octal digits: 274 (base 8).Match option formatting with trailing 8: 2748.Verification / Alternative check:
Round-trip: 2→010, 7→111, 4→100; concatenation recreates 010111100. The mapping is consistent.
Why Other Options Are Wrong:
1728 and 1748: first digit 1 would require leading bits 001 (not present here).
2728: middle digit 7 is correct, but the final digit 2 would require last group 010, whereas we have 100 → 4.
Common Pitfalls:
Grouping from the left instead of the right, or forgetting to pad on the leftmost side. Always ensure the total bit count is a multiple of three before conversion.
Final Answer:
2748