Which of the following formulas represents the \(n\)th term of an AP in which each successive term decreases by 3?
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Answer and explanation
Correct answer: \(a_n=12-3n\)
In an AP, \(a_{n+1}-a_n\) must be constant. For option A, \((12-3(n+1))-(12-3n)=-3\), so every next term decreases by 3. Option B increases instead. Exam tip: check the coefficient of \(n\) in a linear term formula.
Frequently asked questions
What is the correct answer to this question?
\(a_n=12-3n\)
Why is this the correct answer?
In an AP, \(a_{n+1}-a_n\) must be constant. For option A, \((12-3(n+1))-(12-3n)=-3\), so every next term decreases by 3. Option B increases instead. Exam tip: check the coefficient of \(n\) in a linear term formula.
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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