In an AP, (a_5=18) and (a_9=34). What is the common difference?
Answer and explanation
Correct answer: 4
In an AP, the difference between two terms equals the difference in their positions multiplied by the common difference. Thus, \(a_9-a_5=(9-5)d\), so \(34-18=4d\). Hence \(16=4d\) and \(d=4\). Option 16 is the difference between the two given terms, not the common difference. Exam tip: find the difference in term numbers first, then divide the term difference by it.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
In an AP, the difference between two terms equals the difference in their positions multiplied by the common difference. Thus, \(a_9-a_5=(9-5)d\), so \(34-18=4d\). Hence \(16=4d\) and \(d=4\). Option 16 is the difference between the two given terms, not the common difference. Exam tip: find the difference in term numbers first, then divide the term difference by it.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Introduction to APs and common difference..
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