What is the common difference in the sequence (100,90,80,70,\ldots)?
Answer and explanation
Correct answer: -10
To find the common difference, subtract a term from the term immediately before it: \(90-100=-10\). Therefore, the correct answer is \(-10\). Option A gives only the magnitude of the difference, but a decreasing sequence has a negative common difference. Exam tip: calculate second term − first term using any two consecutive terms.
Frequently asked questions
What is the correct answer to this question?
-10
Why is this the correct answer?
To find the common difference, subtract a term from the term immediately before it: \(90-100=-10\). Therefore, the correct answer is \(-10\). Option A gives only the magnitude of the difference, but a decreasing sequence has a negative common difference. Exam tip: calculate second term − first term using any two consecutive terms.
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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