Multiple choice

Directions: Find the wrong term in the following number series: 3.5, 5, 8, 15, 26, 50, 98

  1. 15

  2. 8

  3. 50

  4. 98

  5. 5
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A Correct answer
Explanation

The pattern is: 3.5 * 2 - 2 = 5; 5 * 2 - 2 = 8; 8 * 2 - 1 = 15 (should be 8 * 2 - 2 = 14); 14 * 2 - 2 = 26; 26 * 2 - 2 = 50; 50 * 2 - 2 = 98. The term 15 is incorrect.

AI explanation

The pattern requires subtracting 0.5, then 1, then 2, then 4, then 8, and finally 16 from the successive terms. Subtracting these values means the fourth term should be calculated as 8 minus 2, which is 6. Since 15 appears in the place of 6, it is the incorrect number in the series. The result is 15.

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