In an AP, (a=9) and (d=6). If (S_n=525), what is the value of (n)?
Answer and explanation
Correct answer: (10)
Solving (\frac{n}{2}[18+6(n-1)]=525) gives (n=10). For (n), a quadratic may appear, so choose the positive value.
Frequently asked questions
What is the correct answer to this question?
(10)
Why is this the correct answer?
Solving (\frac{n}{2}[18+6(n-1)]=525) gives (n=10). For (n), a quadratic may appear, so choose the positive value.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Finding the sum of the first $n$ terms of an AP.
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