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Which Term of the A.P. 4, 9, 14, ... is 254? - Mathematics

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Question

Which term of the A.P. 4, 9, 14, ... is 254?

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Solution

 4, 9, 14...
Here, we have:
a = 4

\[d = \left( 9 - 4 \right) = 5\]

\[\text { Let } a_n = 254\]

\[ \Rightarrow a + \left( n - 1 \right) d = 254\]

\[ \Rightarrow 4 + \left( n - 1 \right) 5 = 254\]

\[ \Rightarrow \left( n - 1 \right) 5 = 250\]

\[ \Rightarrow \left( n - 1 \right) = 50\]

\[ \Rightarrow n = 51\]

Hence, 254 is the 51st term of the given A.P.

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Chapter 19: Arithmetic Progression - Exercise 19.2 [Page 12]

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RD Sharma Mathematics [English] Class 11
Chapter 19 Arithmetic Progression
Exercise 19.2 | Q 3.3 | Page 12

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