What is the (18)th term in the AP (11,14,17,20,\ldots)?
Answer and explanation
Correct answer: 62
In this AP, the first term is \(a=11\) and the common difference is \(d=14-11=3\). The \(n\)th term is given by \(a_n=a+(n-1)d\). Therefore, \(a_{18}=11+(18-1)\times3=11+51=62\). Hence, 62 is correct. A value such as 60 can result from an incorrect term count. Exam tip: use \(n-1\), not \(n\), when finding the \(n\)th term of an AP.
Frequently asked questions
What is the correct answer to this question?
62
Why is this the correct answer?
In this AP, the first term is \(a=11\) and the common difference is \(d=14-11=3\). The \(n\)th term is given by \(a_n=a+(n-1)d\). Therefore, \(a_{18}=11+(18-1)\times3=11+51=62\). Hence, 62 is correct. A value such as 60 can result from an incorrect term count. Exam tip: use \(n-1\), not \(n\), when finding the \(n\)th term of an AP.
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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