Multiple choice

Directions: In the following number series, one of the numbers is wrong in the sense that it does not belong to the series. Find that number. 115, 95, 70, 40, 10, -35, -80

  1. 95

  2. 10

  3. 40

  4. -35
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B Correct answer
Explanation

Pattern: 115 - 20 = 95, 95 - 25 = 70, 70 - 30 = 40, 40 - 35 = 5, 5 - 40 = -35, -35 - 45 = -80. The term 10 is wrong; it should be 5.

AI explanation

Using the method of differences, the subtractions between terms are 95 - 115 = -20, 70 - 95 = -25, 40 - 70 = -30, and -35 - 40 = -75. The pattern shows the subtrahend increasing by 5 each time, so the sequence of differences should be -20, -25, -30, -35, -40, and -45. Since the difference after 40 should be -35, the next term should be 5, which makes the number 10 incorrect. The result is 10.

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