What will be the sum of natural numbers from (40) to (80)?
Answer and explanation
Correct answer: 2460
There are \(80-40+1=41\) terms from 40 to 80. Therefore, the sum is \(\frac{41(40+80)}{2}=41\times 60=2460\). Option 2420 may result from an error in counting the terms or finding the average. Exam tip: the number of integers from a first value to a last value is always \(\text{last}-\text{first}+1\).
Frequently asked questions
What is the correct answer to this question?
2460
Why is this the correct answer?
There are \(80-40+1=41\) terms from 40 to 80. Therefore, the sum is \(\frac{41(40+80)}{2}=41\times 60=2460\). Option 2420 may result from an error in counting the terms or finding the average. Exam tip: the number of integers from a first value to a last value is always \(\text{last}-\text{first}+1\).
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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
