What is the (8)th term in the AP (72,66,60,54,\ldots)?
Answer and explanation
Correct answer: 30
For this AP, the first term is \(a=72\) and the common difference is \(d=66-72=-6\). The \(n\)th term is \(a_n=a+(n-1)d\). Hence, \(a_8=72+(8-1)(-6)=72-42=30\). Therefore, 30 is correct. The number 36 is the sixth term, not the eighth term. Exam tip: use the common difference \(n-1\) times to find the \(n\)th term.
Frequently asked questions
What is the correct answer to this question?
30
Why is this the correct answer?
For this AP, the first term is \(a=72\) and the common difference is \(d=66-72=-6\). The \(n\)th term is \(a_n=a+(n-1)d\). Hence, \(a_8=72+(8-1)(-6)=72-42=30\). Therefore, 30 is correct. The number 36 is the sixth term, not the eighth term. Exam tip: use the common difference \(n-1\) times to find the \(n\)th 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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