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 191-200 of 600 questions.
What is the value of \(S_{64}-S_{63}\)?
C. (64)
दो लगातार योगों का अंतर नया पद होता है इसलिए \(S_{64}-S_{63}=64\)। पूरा योग निकाले बिना उत्तर मिल सकता है। / The difference of two consecutive sums is the new term, so \(S_{64}-S_{63}=64\). You can answer without finding full sums.
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If the sum of the first (t) natural numbers is (231), what is the value of (t+5)?
B. (26)
\(S_{21}=231\) इसलिए (t=21) और (t+5=26)। पहले चर का मान निकालें फिर पूछा गया मान दें। / \(S_{21}=231\), so (t=21) and (t+5=26). First find the variable and then answer what is asked.
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What will be the sum of the first (68) natural numbers?
A. (2346)
\(S_{68}=\frac{68\times69}{2}=2346\) है। (68) का आधा (34) लेकर \(34\times69\) करें। / \(S_{68}=\frac{68\times69}{2}=2346\). Take half of (68) as (34) and calculate \(34\times69\).
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What is the value of \(S_{13}+S_{16}+S_{20}\)?
B. (437)
\(S_{13}=91\), \(S_{16}=136\) और \(S_{20}=210\) इसलिए कुल (437) है। तीन योगों को अलग-अलग लिखकर जोड़ें। / \(S_{13}=91\), \(S_{16}=136\), and \(S_{20}=210\), so the total is (437). Write the three sums separately and add.
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If \(S_a=820\) and \(S_b=1035\), what is (b-a)?
C. (5)
\(S_{40}=820\) और \(S_{45}=1035\) इसलिए (b-a=5)। पहले दोनों योगों के सूचकांक पहचानें। / \(S_{40}=820\) and \(S_{45}=1035\), so (b-a=5). First identify the indices of both sums.
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What sum is obtained by adding (53+54+55) to \(1+2+\cdots+52\)?
A. (1540)
यह \(S_{55}\) बनेगा और \(S_{55}=1540\) है। लगातार अगले पद जोड़ने पर नया अंतिम पद (n) होता है। / This becomes \(S_{55}\), and \(S_{55}=1540\). Adding consecutive next terms makes the new last term (n).
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What is the sum of the first (80) natural numbers?
B. (3240)
\(S_{80}=\frac{80\times81}{2}=3240\) है। बड़े (n) में पहले (2) से कटौती करें। / \(S_{80}=\frac{80\times81}{2}=3240\). For large (n), cancel by (2) first.
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If \(S_n=1596\), what will be the value of (n)?
C. (56)
\(S_{56}=\frac{56\times57}{2}=1596\) इसलिए (n=56)। उत्तर को सूत्र में रखकर जांचें। / \(S_{56}=\frac{56\times57}{2}=1596\), so (n=56). Check the answer by substituting it in the formula.
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Find the value of \(S_{25}+S_{27}\).
A. (703)
\(S_{25}=325\) और \(S_{27}=378\) इसलिए योग (703) है। पास-पास के सूचकांक देखकर गलती न करें। / \(S_{25}=325\) and \(S_{27}=378\), so the sum is (703). Do not make a mistake with nearby indices.
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B. (325)
अंतर (63+64+65+66+67=325) है। दो योगों का अंतर बीच के पदों का योग देता है। / The difference is (63+64+65+66+67=325). The difference of two sums gives the sum of the terms in between.
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