If an arithmetic progression has first term 7 and common difference 5, which of the following expressions correctly represents its nth term?
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Answer and explanation
Correct answer: \(a_n=7+5(n-1)\)
The standard nth-term formula of an AP is \(a_n=a+(n-1)d\). Here \(a=7\) and \(d=5\), so \(a_n=7+5(n-1)\). In option A, substituting \(n=1\) gives 12, not 7. Exam tip: always check the \((n-1)\) factor.
Frequently asked questions
What is the correct answer to this question?
\(a_n=7+5(n-1)\)
Why is this the correct answer?
The standard nth-term formula of an AP is \(a_n=a+(n-1)d\). Here \(a=7\) and \(d=5\), so \(a_n=7+5(n-1)\). In option A, substituting \(n=1\) gives 12, not 7. Exam tip: always check the \((n-1)\) factor.
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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