In class, numbers from (1) to (31) were written and their sum was asked. What is the correct answer?
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Answer and explanation
Correct answer: 496
The sum of natural numbers from 1 to \(n\) is \(\frac{n(n+1)}{2}\). Here, \(n=31\), so \(\frac{31\times 32}{2}=31\times 16=496\). Therefore, 496 is correct. The value 465 is the sum from 1 to 30, so it is a close but incorrect distractor. Exam tip: use the last number in the series as \(n\).
Frequently asked questions
What is the correct answer to this question?
496
Why is this the correct answer?
The sum of natural numbers from 1 to \(n\) is \(\frac{n(n+1)}{2}\). Here, \(n=31\), so \(\frac{31\times 32}{2}=31\times 16=496\). Therefore, 496 is correct. The value 465 is the sum from 1 to 30, so it is a close but incorrect distractor. Exam tip: use the last number in the series as \(n\).
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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