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Question: Answered & Verified by Expert
The number of terms in the series $101+99+97+\ldots . .+47$ is
MathematicsSequences and SeriesJEE Main
Options:
  • A $25$
  • B $28$
  • C $30$
  • D $20$
Solution:
1975 Upvotes Verified Answer
The correct answer is: $28$
Given series $101+99+97+\ldots \ldots \ldots .+47$
So, first term $a=101$, common difference $d=-2$ and last term $I=47$
We know that last term of a series
$T_1=a+(n-1) d \Rightarrow 47=101+(n-1)(-2)$
$\Rightarrow-54=(n-1)(-2) \Rightarrow n=28$

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