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 571-580 of 600 questions.
If \(S_{n+1}-S_{n-4}=695\), what will be the value of (n)?
D. (140)
यह अंतर ((n-3)+(n-2)+(n-1)+n+(n+1)=5n-5) है। (5n-5=695) से (n=140)। / This difference is ((n-3)+(n-2)+(n-1)+n+(n+1)=5n-5). From (5n-5=695), (n=140).
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What is the sum of natural numbers from (75) to (125)?
A. (5100)
योग \(S_{125}-S_{74}=7875-2775=5100\) है। निचली सीमा से पहले का योग घटाएं। / The sum is \(S_{125}-S_{74}=7875-2775=5100\). Subtract the sum before the lower limit.
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What is the value of \(S_{120}-S_{80}+S_{40}\)?
B. (4840)
\(S_{120}-S_{80}+S_{40}=7260-3240+820=4840\)। हर आंशिक योग अलग लिखें। / \(S_{120}-S_{80}+S_{40}=7260-3240+820=4840\). Write each partial sum separately.
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If \(S_n=10440\), what is the value of (n)?
C. (144)
\(\frac{144\cdot145}{2}=10440\), इसलिए (n=144)। सूत्र में विकल्प रखकर उत्तर जांचें। / \(\frac{144\cdot145}{2}=10440\), so (n=144). Check the answer by substituting options in the formula.
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If \(S_n-S_{n-2}=257\), what is the value of \(S_n\)?
D. (8385)
\(S_n-S_{n-2}=2n-1\) है। (2n-1=257) से (n=129), अतः \(S_{129}=8385\)। / \(S_n-S_{n-2}=2n-1\). From (2n-1=257), (n=129), so \(S_{129}=8385\).
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Find the sum of natural numbers from (181) to (240).
A. (12630)
योग \(S_{240}-S_{180}=28920-16290=12630\) है। बड़े अंतराल में घटाव विधि तेज होती है। / The sum is \(S_{240}-S_{180}=28920-16290=12630\). The subtraction method is quick for large intervals.
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What is the ratio of the sums of the first (128) and first (64) natural numbers?
C. (258:65)
\(S_{128}:S_{64}=8256:2080=258:65\)। अनुपात को सरलतम रूप में लिखें। / \(S_{128}:S_{64}=8256:2080=258:65\). Write the ratio in simplest form.
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If \(S_n=8256\), what will be \(S_{n+5}-S_n\)?
B. (655)
\(8256=S_{128}\), इसलिए अंतर (129+130+131+132+133=655) है। अगले पांच पदों को जोड़ें। / \(8256=S_{128}\), so the difference is (129+130+131+132+133=655). Add the next five terms.
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If \(S_n+S_{n-1}=12544\) and \(S_n-S_{n-1}=112\), what is the value of \(S_n\)?
C. (6328)
दोनों समीकरण जोड़ने पर \(2S_n=12656\), इसलिए \(S_n=6328\)। समीकरणों को जोड़ना सबसे तेज है। / Adding the two equations gives \(2S_n=12656\), so \(S_n=6328\). Adding the equations is the fastest way.
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If \(S_n=1830\), what will be the value of \(S_{3n}\)?
D. (16290)
\(1830=S_{60}\), इसलिए (3n=180) और \(S_{180}=16290\)। पहले (n) पहचानें। / \(1830=S_{60}\), so (3n=180) and \(S_{180}=16290\). Identify (n) first.
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