Find the sum of the first (31) natural numbers.
Answer and explanation
Correct answer: 496
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{31}=\frac{31\times32}{2}=31\times16=496\). Option 512 results from incorrectly using 32 in place of 31. Exam tip: When finding the sum up to \(n\), remember that the formula includes \(n+1\).
Frequently asked questions
What is the correct answer to this question?
496
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(S_n=\frac{n(n+1)}{2}\). Therefore, \(S_{31}=\frac{31\times32}{2}=31\times16=496\). Option 512 results from incorrectly using 32 in place of 31. Exam tip: When finding the sum up to \(n\), remember that the formula includes \(n+1\).
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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