Multiple choice

Find the missing term in the given series. 15, 18, 24, 35, 53, (?)

  1. 67

  2. 75

  3. 77

  4. 80

  5. 86
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D Correct answer
Explanation

Differences: 18-15=3, 24-18=6, 35-24=11, 53-35=18. Second differences: 6-3=3, 11-6=5, 18-11=7. The next second difference should be 9. 18+9=27. 53+27=80.

AI explanation

The differences between the consecutive terms are 3, 6, 11, and 18. The second differences are 3, 5, and 7, which form a sequence of consecutive odd numbers, meaning the next second difference will be 9. Adding 9 to 18 gives a first difference of 27, and adding 27 to 53 results in 80.

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