QuizCosmo

Classical IQ test

Complete the sequence: 3, 5, 11, 21, 43, ___ .

100%
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Incorrect!

Each number alternates between ×2 −1 and ×2 +1: 3→5 (×2−1), 5→11 (×2+1), 11→21 (×2−1), 21→43 (×2+1), so 43→87 (×2+1).

Complete the sequence: 3, 5, 11, 21, 43, ___ .

63
75
85
87
100%
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