Practice focused topic-wise MCQs with answers and explanations for quick revision and exam preparation.
Difficulty select karke sirf is topic ke focused MCQs practice karein. Score, timer aur explanations student-friendly flow me milenge.
Showing 521-530 of 600 questions.
If \(S_n=15400\), what is the value of \(S_{n-10}\)?
C. (13545)
\(15400=S_{175}\), इसलिए \(S_{165}=\frac{165\cdot166}{2}=13695\) है। दिए विकल्पों में सही मान नहीं है। / \(15400=S_{175}\), so \(S_{165}=\frac{165\cdot166}{2}=13695\). The listed options do not contain the correct value.
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If \(S_n+S_{n-2}=10000\) and \(S_n-S_{n-2}=199\), what will \(S_n\) be?
B. (5099.5)
दोनों समीकरण जोड़ने पर \(2S_n=10199\), इसलिए \(S_n=5099.5\)। ऐसे मानों से प्रश्न की संगति भी जांचें। / Adding the two equations gives \(2S_n=10199\), so \(S_n=5099.5\). Such values also help check the consistency of the question.
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How much is the sum of natural numbers from (201) to (250)?
A. (11275)
योग \(S_{250}-S_{200}=31375-20100=11275\) है। बड़े अंतराल में घटाव विधि तेज होती है। / The sum is \(S_{250}-S_{200}=31375-20100=11275\). The subtraction method is quick for large intervals.
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If \(S_{n+1}-S_{n-4}=595\), what will be the value of (n)?
B. (118)
(S_{n+1}-S_{n-4}=(n-3)+(n-2)+(n-1)+n+(n+1)=5n-5)। (5n-5=595) से (n=120)। / (S_{n+1}-S_{n-4}=(n-3)+(n-2)+(n-1)+n+(n+1)=5n-5). From (5n-5=595), (n=120).
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What is the difference between the sums of the first (180) and first (90) natural numbers?
A. (12195)
\(S_{180}-S_{90}=16290-4095=12195\)। यह (91) से (180) तक का योग है। / \(S_{180}-S_{90}=16290-4095=12195\). This is the sum from (91) to (180).
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If \(S_n=8911\), what is the value of (n)?
B. (133)
\(\frac{133\cdot134}{2}=8911\), इसलिए (n=133)। विकल्पों को सूत्र में रखकर सत्यापित करें। / \(\frac{133\cdot134}{2}=8911\), so (n=133). Verify the options by substituting them into the formula.
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If \(S_n=7140\), what is the value of \(S_{n+5}-S_n\)?
C. (605)
\(7140=S_{119}\), इसलिए अंतर (120+121+122+123+124=610) है। सही विकल्प (D) होना चाहिए। / \(7140=S_{119}\), so the difference is (120+121+122+123+124=610). The correct option should be (D).
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What will be the sum of natural numbers from (81) to (144)?
A. (7200)
योग \(S_{144}-S_{80}=10440-3240=7200\) है। (81) से शुरू हो तो (80) तक का योग घटाएं। / The sum is \(S_{144}-S_{80}=10440-3240=7200\). If it starts from (81), subtract the sum up to (80).
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If \(S_n-S_{100}=15150\), what is the value of (n)?
C. (200)
\(S_{200}-S_{100}=20100-5050=15050\), इसलिए दिए विकल्पों में (15150) का सही मिलान नहीं है। अंतर हमेशा जांचें। / \(S_{200}-S_{100}=20100-5050=15050\), so none of the listed options matches (15150). Always check the difference.
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A. (2054)
\(S_{78}-S_{52}+S_{26}=3081-1378+351=2054\)। हर आंशिक योग अलग लिखें। / \(S_{78}-S_{52}+S_{26}=3081-1378+351=2054\). Write each partial sum separately.
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