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The (n)th term of a sequence is (a_n=3n-8). What is (a_1+a_{15})?
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Answer and explanation
Correct answer: \(32\)
Given \(a_n=3n-8\), \(a_1=3(1)-8=-5\) and \(a_{15}=3(15)-8=37\). Therefore, \(a_1+a_{15}=-5+37=32\). Option \(37\) is only the 15th term, not the required sum. Exam tip: substitute each value of \(n\) separately before adding the terms.
Frequently asked questions
What is the correct answer to this question?
\(32\)
Why is this the correct answer?
Given \(a_n=3n-8\), \(a_1=3(1)-8=-5\) and \(a_{15}=3(15)-8=37\). Therefore, \(a_1+a_{15}=-5+37=32\). Option \(37\) is only the 15th term, not the required sum. Exam tip: substitute each value of \(n\) separately before adding the terms.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: nth term.
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