A child found the sum of natural numbers from (1) to (54). What is the correct sum?
Answer and explanation
Correct answer: 1485
The sum of the first 54 natural numbers is found using \(S_n=\frac{n(n+1)}{2}\). Thus, \(S_{54}=\frac{54\times55}{2}=27\times55=1485\). Therefore, 1485 is correct. A value such as 1475 can result from an error while multiplying or dividing by 2. Exam tip: Substitute the last natural number for \(n\) in the formula.
Frequently asked questions
What is the correct answer to this question?
1485
Why is this the correct answer?
The sum of the first 54 natural numbers is found using \(S_n=\frac{n(n+1)}{2}\). Thus, \(S_{54}=\frac{54\times55}{2}=27\times55=1485\). Therefore, 1485 is correct. A value such as 1475 can result from an error while multiplying or dividing by 2. Exam tip: Substitute the last natural number for \(n\) 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.
