If (a_2=18) and (d=6), what is (a_1)?
Answer and explanation
Correct answer: \(12\)
In an arithmetic progression, the second term is \(a_2=a_1+d\). Therefore, \(a_1=a_2-d=18-6=12\). Hence, the correct answer is \(12\). Getting \(24\) would mean adding the common difference instead of subtracting it, which is incorrect here. Exam tip: subtract the common difference when moving back to the first term.
Frequently asked questions
What is the correct answer to this question?
\(12\)
Why is this the correct answer?
In an arithmetic progression, the second term is \(a_2=a_1+d\). Therefore, \(a_1=a_2-d=18-6=12\). Hence, the correct answer is \(12\). Getting \(24\) would mean adding the common difference instead of subtracting it, which is incorrect here. Exam tip: subtract the common difference when moving back to the first 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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