In an arithmetic progression, the first term is (18) and the sixteenth term is (93), what is the common difference?
Answer and explanation
Correct answer: 5
For an arithmetic progression, the nth-term formula is \(a_n=a+(n-1)d\). Here, \(93=18+(16-1)d\), so \(93=18+15d\). Thus, \(15d=75\) and \(d=5\). The value 6 can result from incorrectly counting the number of gaps between the first and sixteenth terms. Exam tip: there are always \(n-1\) gaps from the first term to the nth term.
Frequently asked questions
What is the correct answer to this question?
5
Why is this the correct answer?
For an arithmetic progression, the nth-term formula is \(a_n=a+(n-1)d\). Here, \(93=18+(16-1)d\), so \(93=18+15d\). Thus, \(15d=75\) and \(d=5\). The value 6 can result from incorrectly counting the number of gaps between the first and sixteenth terms. Exam tip: there are always \(n-1\) gaps from the first term to the nth term.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Arithmetic Progression.
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