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Which one of the given options is a possible value of x in the following sequence? 3, 7, 15, x, 63, 127, 255

1. 35
2. 40
3. 45
4. 31

Correct answer: 31

Solution

The sequence follows a pattern where each term is one less than a power of 2: 3 (2² - 1), 7 (2³ - 1), 15 (2⁴ - 1), 31 (2⁵ - 1), 63 (2⁶ - 1), 127 (2⁷ - 1), and 255 (2⁸ - 1). Thus, 31 is the only option that fits this pattern.

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