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Find the sum 9+15+27+....+195.

A) 3244
B) 3344
C) 3264
D) 3364

Correct Answer:



C) 3264

Description for Correct answer:
Here a=9, d=6, t=195

Therefore, \( \Large n=\frac{l-a}{d}+1 \)

=\( \Large \frac{195-9}{6}+1 = \frac{186}{6}+1 = 32 \)

\( \Large S_{n} =\frac{n}{2} \left(2a \left(n-1\right)d \right) \)

\( \Large \frac{32}{2} \{ 18+ \left(32-1\right) \times 6 \} \)

=\( \Large 16 \left(18+31 \times 6\right) \)

=\( \Large 16 \left(18+186\right) \)

=\( \Large 16 \times 204 = 3264 \)

Part of solved Factorisation questions and answers : >> Elementary Mathematics >> Factorisation

Comments

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