In the sequence (7, 15, 31, 63, 127, ...), each next term is obtained by doubling the previous term and adding 1. What will be the next term?
Answer and explanation
Correct answer: 255
The governing concept is a recursive sequence: each term is calculated from the term immediately before it. The rule is next term = 2 × previous term + 1. Using the last given term, 2 × 127 + 1 = 254 + 1 = 255, so option C is correct. Options A and B result from incorrect arithmetic, while D does not follow the stated rule.
Frequently asked questions
What is the correct answer to this question?
255
Why is this the correct answer?
The governing concept is a recursive sequence: each term is calculated from the term immediately before it. The rule is next term = 2 × previous term + 1. Using the last given term, 2 × 127 + 1 = 254 + 1 = 255, so option C is correct. Options A and B result from incorrect arithmetic, while D does not follow the stated rule.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Recursive rule.
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