If (a=8) and (d=9), what will be the (10)th term of the AP?
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Answer and explanation
Correct answer: 89
The formula for the nth term of an AP is \(a_n=a+(n-1)d\). Thus, \(a_{10}=8+(10-1)\times 9=8+81=89\). Therefore, 89 is correct. The value 90 can result from an incorrect use of the common difference. Exam tip: for the nth term, use \((n-1)\), not \(n\).
Frequently asked questions
What is the correct answer to this question?
89
Why is this the correct answer?
The formula for the nth term of an AP is \(a_n=a+(n-1)d\). Thus, \(a_{10}=8+(10-1)\times 9=8+81=89\). Therefore, 89 is correct. The value 90 can result from an incorrect use of the common difference. Exam tip: for the nth term, use \((n-1)\), not \(n\).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Finding the $n$th term of an AP.
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