In an AP, (a=17), (d=1). What is the (40)th term?
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Answer and explanation
Correct answer: 56
The nth term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{40}=17+(40-1)\times1=17+39=56\). Hence, 56 is correct. Getting 55 is an off-by-one error, because 39 common differences are added after the first term. Exam tip: always use \(n-1\) when finding the nth term.
Frequently asked questions
What is the correct answer to this question?
56
Why is this the correct answer?
The nth term of an AP is \(a_n=a+(n-1)d\). Therefore, \(a_{40}=17+(40-1)\times1=17+39=56\). Hence, 56 is correct. Getting 55 is an off-by-one error, because 39 common differences are added after the first term. Exam tip: always use \(n-1\) when finding the nth 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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