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NDA 2012
Exam
NDA
Year
2012
Subject
Mathematics
Chapter
Sequences and Series

NDA 2012 · Mathematics · Sequences and Series

What is the arithmetic mean of first 16 natural numbers with...

What is the arithmetic mean of first 16 natural numbers with weights being the number itself?

Options

  1. A1712\frac{17}{12}
  2. B332\frac{33}{2}
  3. C11
  4. D1872\frac{187}{2}

Correct answer

A. 1712\frac{17}{12}

Step-by-step solution

S16=162[2(1)+15(1)]=8(17)=136 A.M. =13616=172. \begin{aligned} & \mathrm{S}_{16}=\frac{16}{2}[2(1)+15(1)] \\ & =8(17) \\ & =136 \\ & \text{ A.M. }=\frac{136}{16}=\frac{17}{2} \text{. } \end{aligned}
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