Which is the sum of the first (30) natural numbers?
Answer and explanation
Correct answer: 465
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Substituting \(n=30\), we get \(\frac{30\times31}{2}=15\times31=465\). Therefore, 465 is correct. The value 450 may result from an incorrect calculation rather than using the sum from 1 to 30. Exam tip: In such questions, remember to use both \(n\) and \(n+1\) in \(n(n+1)/2\).
Frequently asked questions
What is the correct answer to this question?
465
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Substituting \(n=30\), we get \(\frac{30\times31}{2}=15\times31=465\). Therefore, 465 is correct. The value 450 may result from an incorrect calculation rather than using the sum from 1 to 30. Exam tip: In such questions, remember to use both \(n\) and \(n+1\) in \(n(n+1)/2\).
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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