In an AP, \(a=9\) and \(d=\frac{5}{2}\). What is \(a_{17}\)?
Answer and explanation
Correct answer: 49
The \(n\)th term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{17}=9+(17-1)\times\frac{5}{2}=9+16\times\frac{5}{2}=9+40=49\). Hence, the correct answer is 49. Getting 47 would result from using the number of differences incorrectly. Exam tip: for the \(n\)th term, use \(n-1\) common differences, not \(n\).
Frequently asked questions
What is the correct answer to this question?
49
Why is this the correct answer?
The \(n\)th term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{17}=9+(17-1)\times\frac{5}{2}=9+16\times\frac{5}{2}=9+40=49\). Hence, the correct answer is 49. Getting 47 would result from using the number of differences incorrectly. Exam tip: for the \(n\)th term, use \(n-1\) common differences, not \(n\).
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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