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Class 9MathematicsSequences and ProgressionsSum of first n natural numbersEasyLevel 63
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If (S_n=120) and (S_n) is the sum of the first (n) natural numbers, what is (n)?

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Answer and explanation

Correct answer: (15)

(S_{15}=120) because (\frac{15\times16}{2}=120). In such questions, verify the answer back in the formula.

Related tags

MathSequencesNatural-NumbersSum

Frequently asked questions

What is the correct answer to this question?

(15)

Why is this the correct answer?

(S_{15}=120) because (\frac{15\times16}{2}=120). In such questions, verify the answer back in the formula.

Which subject and chapter does this question cover?

This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Sum of first n natural numbers.

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