If (a_n=6n-4), which term will be equal to (62)?
Answer and explanation
Correct answer: 11th
The governing concept is using an explicit sequence rule to identify the position of a specified term. Set the general term equal to the required value: 6n−4=62. Add 4 to both sides to obtain 6n=66, and divide by 6 to obtain n=11. Hence 62 is the 11th term, so option C is correct. Verification is immediate: a_11=6(11)−4=66−4=62. The other choices would produce a_9=50, a_10=56, and a_12=68, respectively, so they cannot equal 62. The important method is to solve for the index n rather than substitute the given value into the wrong part of the formula.
Frequently asked questions
What is the correct answer to this question?
11th
Why is this the correct answer?
The governing concept is using an explicit sequence rule to identify the position of a specified term. Set the general term equal to the required value: 6n−4=62. Add 4 to both sides to obtain 6n=66, and divide by 6 to obtain n=11. Hence 62 is the 11th term, so option C is correct. Verification is immediate: a_11=6(11)−4=66−4=62. The other choices would produce a_9=50, a_10=56, and a_12=68, respectively, so they cannot equal 62. The important method is to solve for the index n rather than substitute the given value into the wrong part of the formula.
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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