What is the sum of natural numbers from (401) to (450)?
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Answer and explanation
Correct answer: 21275
There are 50 terms from 401 to 450. Their average is \(\frac{401+450}{2}=425.5\). Therefore, the sum is \(50\times 425.5=21275\). A value such as 21375 can result from a small error in counting terms or finding the average. Exam tip: for an inclusive interval, the number of terms is \(last-first+1\).
Frequently asked questions
What is the correct answer to this question?
21275
Why is this the correct answer?
There are 50 terms from 401 to 450. Their average is \(\frac{401+450}{2}=425.5\). Therefore, the sum is \(50\times 425.5=21275\). A value such as 21375 can result from a small error in counting terms or finding the average. Exam tip: for an inclusive interval, the number of terms is \(last-first+1\).
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.
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