The (n)th term of an arithmetic sequence is (a_n=9n-13). Which term is (122)?
Answer and explanation
Correct answer: 15th
Given \(a_n=9n-13\) and the term value is \(122\), set \(9n-13=122\). Thus, \(9n=135\), so \(n=15\). Hence, \(122\) is the 15th term of the sequence. The close distractor, the 14th term, is incorrect because \(a_{14}=9(14)-13=113\). Exam tip: To find the position of a given term, equate \(a_n\) to that term’s value.
Frequently asked questions
What is the correct answer to this question?
15th
Why is this the correct answer?
Given \(a_n=9n-13\) and the term value is \(122\), set \(9n-13=122\). Thus, \(9n=135\), so \(n=15\). Hence, \(122\) is the 15th term of the sequence. The close distractor, the 14th term, is incorrect because \(a_{14}=9(14)-13=113\). Exam tip: To find the position of a given term, equate \(a_n\) to that term’s value.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: nth term.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
