Octal to Decimal — Positional Evaluation Convert the octal number 35 (base 8) to its decimal equivalent. Show the weighted sum explicitly.
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A71
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B17
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C92
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D29
Answer
Correct Answer: 29
Explanation
Introduction / Context:Converting from octal to decimal uses positional weights that are powers of eight. This reinforces the general positional numeral system concept used across all bases.
Given Data / Assumptions:
- Octal number: 35_8.
- Digit positions from right: 8^0, 8^1, 8^2, and so on.
- Digits are valid octal symbols 0..7.
Concept / Approach:Multiply each digit by its positional weight and add. The rightmost digit multiplies by 8^0 = 1, the next by 8^1 = 8, and so forth.
Step-by-Step Solution:1) Write 35_8 as 38^1 + 58^0.2) Compute weights: 8^1 = 8, 8^0 = 1.3) Evaluate: 38 = 24; 51 = 5.4) Sum: 24 + 5 = 29 decimal.
Verification / Alternative check:Convert 29 back to octal by repeated division by 8: 29 / 8 = 3 remainder 5, reconstructing 35_8.
Why Other Options Are Wrong:
- 71 and 92: Values inconsistent with the small range of two octal digits.
- 17: Result of misplacing digit weights or treating the number as base 10.
Common Pitfalls:Confusing base when evaluating weights, or reading 35 as thirty five decimal instead of base 8 representation.
Final Answer:29