What is the (9)th term of the AP (90,82,74,66,\ldots)?
Answer and explanation
Correct answer: 26
The first term is 90 and the common difference is \(d=82-90=-8\). Using \(a_n=a+(n-1)d\), \(a_9=90+(9-1)(-8)=90-64=26\). Hence, 26 is correct. Option 34 is the 8th term because the common difference is applied only seven times there. Exam tip: for the \(n\)th term, use \(n-1\) common differences.
Frequently asked questions
What is the correct answer to this question?
26
Why is this the correct answer?
The first term is 90 and the common difference is \(d=82-90=-8\). Using \(a_n=a+(n-1)d\), \(a_9=90+(9-1)(-8)=90-64=26\). Hence, 26 is correct. Option 34 is the 8th term because the common difference is applied only seven times there. Exam tip: for the \(n\)th term, use \(n-1\) common differences.
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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