In an AP, \(a=4\) and \(d=\frac{3}{2}\). What is \(a_{13}\)?
Answer and explanation
Correct answer: 22
The \(n\)th term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{13}=4+(13-1)\times\frac{3}{2}=4+12\times\frac{3}{2}=4+18=22\). Hence, 22 is correct. Getting 21 would mean the common difference has not been multiplied correctly. Exam tip: always use \((n-1)\), not \(n\), in the formula for \(a_n\).
Frequently asked questions
What is the correct answer to this question?
22
Why is this the correct answer?
The \(n\)th term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{13}=4+(13-1)\times\frac{3}{2}=4+12\times\frac{3}{2}=4+18=22\). Hence, 22 is correct. Getting 21 would mean the common difference has not been multiplied correctly. Exam tip: always use \((n-1)\), not \(n\), in the formula for \(a_n\).
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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
