In an AP, (a=9), (d=2). Find the (18)th term.
Answer and explanation
Correct answer: 43
The nth term of an arithmetic progression is given by \(a_n=a+(n-1)d\). Thus, \(a_{18}=9+(18-1)\times2=9+34=43\), so the correct answer is 43. The distractor 45 results from incorrectly using \(18d\) instead of \((18-1)d\). Exam tip: always use \(n-1\) when finding the nth term from the first term.
Frequently asked questions
What is the correct answer to this question?
43
Why is this the correct answer?
The nth term of an arithmetic progression is given by \(a_n=a+(n-1)d\). Thus, \(a_{18}=9+(18-1)\times2=9+34=43\), so the correct answer is 43. The distractor 45 results from incorrectly using \(18d\) instead of \((18-1)d\). Exam tip: always use \(n-1\) when finding the nth term from the first term.
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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