What is (a_5) of the geometric progression (12,36,108,324,\ldots)?
Answer and explanation
Correct answer: 972
The common ratio of this geometric progression is \(r=36/12=3\). Since the fourth term is 324, the fifth term is \(a_5=324\times 3=972\). The value 1296 would come from multiplying 324 by 4, which is not the common ratio. Exam tip: obtain each next term by multiplying the previous term by the common ratio.
Frequently asked questions
What is the correct answer to this question?
972
Why is this the correct answer?
The common ratio of this geometric progression is \(r=36/12=3\). Since the fourth term is 324, the fifth term is \(a_5=324\times 3=972\). The value 1296 would come from multiplying 324 by 4, which is not the common ratio. Exam tip: obtain each next term by multiplying the previous term by the common ratio.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Geometric Progression.
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