If the (n)th term of an AP is given by (a_n=4n-1), what is (a_{30})?
Answer and explanation
Correct answer: 119
Given \(a_n=4n-1\), substitute \(n=30\) to find the 30th term: \(a_{30}=4(30)-1=120-1=119\). Therefore, 119 is correct. The value 121 would result from adding 1 instead of subtracting it, so it is not correct. Exam tip: in a direct \(n\)th-term formula, substitute the required term number carefully for \(n\).
Frequently asked questions
What is the correct answer to this question?
119
Why is this the correct answer?
Given \(a_n=4n-1\), substitute \(n=30\) to find the 30th term: \(a_{30}=4(30)-1=120-1=119\). Therefore, 119 is correct. The value 121 would result from adding 1 instead of subtracting it, so it is not correct. Exam tip: in a direct \(n\)th-term formula, substitute the required term number carefully for \(n\).
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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