If {m^{th}} terms of series 63 + 65 + 67 + 69 + ......... and 3 + 10 + 17 + 24 + ...... be equal, th

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8. Sequences and Series

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If ${m^{th}}$ terms of the series $63 + 65 + 67 + 69 + .........$ and $3 + 10 + 17 + 24 + ......$ be equal, then $m = $

A

$11$

B

$12$

C

$13$

D

$15$

Solution

(c) Given series $63 + 65 + 67 + 69 + ……$ …..$(i)$

and $3 + 10 + 17 + 24 + ……$….. $(ii)$

Now from $(i),$ ${m^{th}}$ term $ = (2m + 61)$

and ${m^{th}}$ term of $(ii)$ series $ = (7m – 4)$

Under condition,

$ \Rightarrow 7m – 4 = 2m + 61$

$\Rightarrow 5m = 65$

$\Rightarrow m = 13$.

Standard 11

Mathematics

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