Multiple choice

Directions: Find the wrong number term in the following series. 97, 101, 109, 125, 158, 221

  1. 101

  2. 109

  3. 125

  4. 158

  5. 221
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Differences: 101-97=4 (2^2), 109-101=8 (not a square), 125-109=16 (4^2), 158-125=33 (not a square), 221-158=63 (not a square). Pattern is +4, +8, +16, +32, +64. 97+4=101, 101+8=109, 109+16=125, 125+32=157. 158 is the wrong term.

AI explanation

Calculate the differences between the consecutive terms: 4, 8, 16, 33, and 63. To find the underlying pattern, look at the differences of these differences: 4, 8, 17, and 30. The next level of differences is 4, 9, and 13, which reveals that the increments are increasing. If the first difference was 32 instead of 33, the sequence of second differences would perfectly match the squares of consecutive even numbers or similar logical progression. Therefore, 125 + 32 equals 157, meaning the listed term 158 is incorrect. The result is 158.

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