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Mathematics - Sequence & Series Question with Solution | TestHub

MathematicsSequence & SeriesA.P.Medium2 minQB

MathematicsMediumsingle choice

For $k = 1, \dots, 50$ , let $x_{k}$ be $k$ less than the sum of the other 49 numbers in the sequence. Find $96 x_{20}$ .

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Answer:

Solution:

If $S = \sum_{k = 1}^{50} x_{k}$ , then $2 x_{k} + k = S$ . Summing gives $2 S + 1275 = 50 S$ , so $S = 1275/48$ . Then $96 x_{20} = 48 (S - 20) = 315$ .

Stream:JEESubject:MathematicsTopic:Sequence & SeriesSubtopic:A.P.

⏱ 2mℹ️ Source: QB

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