PCEP-30-02 · Question #284
What is the decimal value of the following binary number?
The correct answer is D. 10. Option D (10) is correct because the binary number 1010 converts to decimal as: 1×2³ + 0×2² + 1×2¹ + 0×2⁰ = 8 + 0 + 2 + 0 = 10. Option A (8) is a common trap - it represents only the leftmost bit (2³ = 8), ignoring the second active bit at position 2¹. Option B (4) corresponds…
Question
Options
- A8
- B4
- C12
- D10
How the community answered
(39 responses)- A8% (3)
- B15% (6)
- C5% (2)
- D72% (28)
Explanation
Option D (10) is correct because the binary number 1010 converts to decimal as: 1×2³ + 0×2² + 1×2¹ + 0×2⁰ = 8 + 0 + 2 + 0 = 10. Option A (8) is a common trap - it represents only the leftmost bit (2³ = 8), ignoring the second active bit at position 2¹. Option B (4) corresponds to the binary 0100, which misidentifies the bit positions entirely. Option C (12) results from adding 8 + 4 (positions 2³ + 2²), as if both middle zeros were ones - confusing 1010 with 1100.
Memory tip: Use the "double and add" method - read bits left to right, doubling your running total and adding the current bit each step: 0→1 (×2+1=1) →2 (×2+0=2) →5 (×2+1=5) →10 (×2+0=10). This eliminates positional arithmetic errors on exam day.
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