If (a_n=50-5n), what is the value of (a_7)?
Answer and explanation
Correct answer: 15
Given \(a_n=50-5n\), substitute \(n=7\) to find the seventh term: \(a_7=50-5(7)=50-35=15\). Therefore, 15 is correct. Getting 20 usually indicates an error in calculating \(5\times7\) or in subtraction. Exam tip: For an explicit rule, substitute the term number for \(n\) and simplify step by step.
Frequently asked questions
What is the correct answer to this question?
15
Why is this the correct answer?
Given \(a_n=50-5n\), substitute \(n=7\) to find the seventh term: \(a_7=50-5(7)=50-35=15\). Therefore, 15 is correct. Getting 20 usually indicates an error in calculating \(5\times7\) or in subtraction. Exam tip: For an explicit rule, substitute the term number for \(n\) and simplify step by step.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Explicit or general rule.
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