Multiple choice

Find the wrong number in the following series. 1760, 865, 420, 210, 92.5, 41.25, 18.125

  1. 865

  2. 210

  3. 92.5

  4. 41.25

  5. 18.125
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B Correct answer
Explanation

The pattern is: 1760 / 2 - 15 = 865; 865 / 2 - 12.5 = 420; 420 / 2 - 10 = 200 (not 210); 200 / 2 - 7.5 = 92.5. The number 210 is incorrect.

AI explanation

The pattern in this sequence requires dividing a term by 2 and then subtracting 5 to arrive at the next term. Dividing 1760 by 2 gives 880, and subtracting 5 gives 875, which means the true second term should be 875 instead of 865. Following this correct rule, 875 divided by 2 is 437.5 minus 5 is 432.5, 432.5 divided by 2 is 216.25 minus 5 is 211.25, and 211.25 divided by 2 is 105.625 minus 5 is 100.625. The provided value 210 is the only number that completely breaks this mathematical progression. The result is 210.

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