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In an AP, (a=3) and (d=10). What will be the (13)th term?
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Answer and explanation
Correct answer: 123
The nth term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{13}=3+(13-1)\times10=3+120=123\). Hence, 123 is correct. The value 120 is only \(12d\); the first term, 3, must also be added. Exam tip: always use \(n-1\), not \(n\), in the nth-term formula.
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What is the correct answer to this question?
123
Why is this the correct answer?
The nth term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{13}=3+(13-1)\times10=3+120=123\). Hence, 123 is correct. The value 120 is only \(12d\); the first term, 3, must also be added. Exam tip: always use \(n-1\), not \(n\), in the nth-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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