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Series and Odd Man out Practice Test 2

Question : 2 of 40

Marks: +1, -0

1, 3, 7, 15, 31, 65, 127, 255

Solution:

Concept:

The series follows the pattern: each term is obtained by doubling the previous term and adding

1

Explanation:

Check the pattern term by term.

1 \times 2 + 1 = 3

3 \times 2 + 1 = 7

7 \times 2 + 1 = 15

15 \times 2 + 1 = 31

31 \times 2 + 1 = 63

, but the series shows

65

65

is the incorrect term.

63 \times 2 + 1 = 127

127 \times 2 + 1 = 255

Thus the wrong term is

65

; it should be

63

Answer:

63

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