Number series — subtract consecutive perfect squares: Complete the series: 41, 40, 36, ?, 11
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A35
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B27
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C29
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D30
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ENone of these
Answer
Correct Answer: 27
Explanation
Introduction / Context:Some decreasing sequences are generated by subtracting perfect squares in order. Recognizing the first few subtractions often reveals the pattern immediately.
Given Data / Assumptions:
- Series: 41, 40, 36, ?, 11
- Observe differences: −1, −4, −9, −16 are 1^2, 2^2, 3^2, 4^2 in order.
Concept / Approach:Subtract successive square numbers starting at 1^2. Insert the missing value that keeps the pattern consistent.
Step-by-Step Solution:41 − 1^2 = 4040 − 2^2 = 3636 − 3^2 = 27 ← missing term27 − 4^2 = 11
Verification / Alternative check:The complete sequence becomes 41, 40, 36, 27, 11 with consecutive subtractions of 1, 4, 9, 16.
Why Other Options Are Wrong:30, 29, or 35 would break the exact squares subtraction cadence.
Common Pitfalls:Mixing up additive and subtractive square patterns; always check a few steps forward.
Final Answer:27