What will be the (7)th term of the AP (50,45,40,35,\ldots)?
Answer and explanation
Correct answer: 20
In this AP, the first term is \(a=50\) and the common difference is \(d=45-50=-5\). The \(n\)th term is \(a_n=a+(n-1)d\). Thus, \(a_7=50+(7-1)(-5)=50-30=20\). Therefore, 20 is correct. The number 25 is the sixth term, so it is a close but incorrect option. Exam tip: always retain the negative sign of \(d\) in a decreasing AP.
Frequently asked questions
What is the correct answer to this question?
20
Why is this the correct answer?
In this AP, the first term is \(a=50\) and the common difference is \(d=45-50=-5\). The \(n\)th term is \(a_n=a+(n-1)d\). Thus, \(a_7=50+(7-1)(-5)=50-30=20\). Therefore, 20 is correct. The number 25 is the sixth term, so it is a close but incorrect option. Exam tip: always retain the negative sign of \(d\) in a decreasing AP.
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.
