Multiple choice

In each of the following question a series is given with one term missing. Choose the correct alternative from the given ones that will complete the series. 1, 9, 25, 81, 329, ?

  1. 1549

  2. 1649

  3. 1650

  4. 1651
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pattern: multiply by increasing integers with alternating additions/subtractions of decreasing numbers. 1 × 2 + 7 = 9, 9 × 3 - 2 = 25, 25 × 3 + 6 = 81, 81 × 4 + 5 = 329. Next: 329 × 5 + 4 = 1649.

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