What is the sum of (1+2+3+\cdots+14)?
Answer and explanation
Correct answer: 105
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Here, \(n=14\), so \(\frac{14\times15}{2}=105\). Therefore, the correct answer is 105. The option 110 may result from an incorrect calculation of \(14\times15\div2\). Exam tip: use the last number as \(n\) in the formula.
Frequently asked questions
What is the correct answer to this question?
105
Why is this the correct answer?
The sum of the first \(n\) natural numbers is \(\frac{n(n+1)}{2}\). Here, \(n=14\), so \(\frac{14\times15}{2}=105\). Therefore, the correct answer is 105. The option 110 may result from an incorrect calculation of \(14\times15\div2\). Exam tip: use the last number as \(n\) 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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