Multiple choice

Find the missing term (?) in the following series: 786, 785, 781, 772, 756, ?

  1. 707

  2. 714

  3. 725

  4. 731

  5. 745
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D Correct answer
Explanation

The differences between consecutive terms are: 786-785=1 (1^2), 785-781=4 (2^2), 781-772=9 (3^2), 772-756=16 (4^2). The next difference should be 5^2=25, so 756-25=731.

AI explanation

The differences between the consecutive terms are successive perfect squares: 785 - 786 = -1 (1 squared), 781 - 785 = -4 (2 squared), 772 - 781 = -9 (3 squared), and 756 - 772 = -16 (4 squared). Continuing this pattern, the next difference must be -25 (5 squared). Subtracting 25 from 756 gives the missing term, which is 731.

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