In the sequence (10,20,30,40,\ldots), which term is (90)?
Answer and explanation
Correct answer: ninth term
Each term in this sequence is a multiple of 10, so its nth term is \(a_n=10n\). Putting \(10n=90\) gives \(n=9\). Therefore, 90 is the ninth term. The tenth term would be 100, so it is not correct. Exam tip: for this sequence, divide the given number by 10 to find its term number quickly.
Frequently asked questions
What is the correct answer to this question?
ninth term
Why is this the correct answer?
Each term in this sequence is a multiple of 10, so its nth term is \(a_n=10n\). Putting \(10n=90\) gives \(n=9\). Therefore, 90 is the ninth term. The tenth term would be 100, so it is not correct. Exam tip: for this sequence, divide the given number by 10 to find its term number quickly.
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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