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 551-560 of 600 questions.
If (S_n=\frac{n(n+1)}{2}) and \(S_n=7503\), what is the value of (n)?
C. (122)
\(\frac{122\cdot123}{2}=7503\), इसलिए (n=122)। बड़े योग में विकल्पों को सूत्र में जांचें। / \(\frac{122\cdot123}{2}=7503\), so (n=122). For a large sum, check options in the formula.
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What is the sum of natural numbers from (56) to (120)?
B. (5720)
योग \(S_{120}-S_{55}=7260-1540=5720\) है। निचली सीमा से एक कम तक का योग घटाएं। / The sum is \(S_{120}-S_{55}=7260-1540=5720\). Subtract the sum up to one less than the lower limit.
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If \(S_n-S_{n-6}=813\), what will be the value of (n)?
D. (138)
\(S_n-S_{n-6}=6n-15\) होता है। (6n-15=813) से (n=138)। / \(S_n-S_{n-6}=6n-15\). From (6n-15=813), (n=138).
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If \(S_{n+4}-S_{n-1}=485\), what is the value of (n)?
A. (95)
यह अंतर (n+(n+1)+(n+2)+(n+3)+(n+4)=5n+10) है। (5n+10=485) से (n=95)। / This difference is (n+(n+1)+(n+2)+(n+3)+(n+4)=5n+10). From (5n+10=485), (n=95).
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If \(S_n=9870\), what is the value of (n)?
B. (140)
\(\frac{140\cdot141}{2}=9870\), इसलिए (n=140)। सम संख्या को आधा करके गुणा करें। / \(\frac{140\cdot141}{2}=9870\), so (n=140). Halve the even number and multiply.
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If \(S_n=2701\), what will be the value of \(S_{n+7}-S_n\)?
D. (539)
\(2701=S_{73}\), इसलिए अंतर \(74+75+\cdots+80=539\) है। अगले सात पदों का योग लें। / \(2701=S_{73}\), so the difference is \(74+75+\cdots+80=539\). Take the sum of the next seven terms.
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What is the ratio of the sums of the first (84) and first (56) natural numbers?
A. (85:38)
\(S_{84}:S_{56}=3570:1596=85:38\)। अनुपात को सरलतम रूप में लिखें। / \(S_{84}:S_{56}=3570:1596=85:38\). Write the ratio in simplest form.
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If \(S_n+S_{n-1}=5625\) and \(S_n-S_{n-1}=75\), what is the value of \(S_n\)?
B. (2850)
दोनों समीकरण जोड़ने पर \(2S_n=5700\), इसलिए \(S_n=2850\)। समीकरणों को जोड़ना तेज तरीका है। / Adding the two equations gives \(2S_n=5700\), so \(S_n=2850\). Adding equations is a quick method.
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How much is the sum of natural numbers from (101) to (160)?
C. (7830)
योग \(S_{160}-S_{100}=12880-5050=7830\) है। बड़े अंतराल में घटाव विधि उपयोग करें। / The sum is \(S_{160}-S_{100}=12880-5050=7830\). Use the subtraction method for large intervals.
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If \(S_n=16290\), what is the value of \(S_{n-8}\)?
D. (14878)
\(16290=S_{180}\), इसलिए \(S_{172}=\frac{172\cdot173}{2}=14878\)। पहले (n) पहचानें फिर (8) कम करें। / \(16290=S_{180}\), so \(S_{172}=\frac{172\cdot173}{2}=14878\). Identify (n) first and then reduce it by (8).
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