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Quantitative Reasoning · Hard · 2 of 16

Number Series puzzle #2 (hard)

Which number comes next? Tap an option to check your answer, or show the answer for the step-by-step solution. Rule in play: doubling gaps.

Plate 02 / 16 · Hard

Which number comes next?

7, 11, 19, 35, 67, ?

Tap the option you think is right, or show the answer.

Show the answer

The next number is 131 (option 4).

How to solve it

  1. Find the gaps between neighbors: 4, 8, 16, 32.
  2. The gaps between the numbers double each time.
  3. So the next gap is 64, and 67 + 64 = 131.
Fig. 1: Number Series #2, hard set. Tap an option to check it.

About this puzzle

Hard series add the two previous numbers, double and add a constant, double the gaps, or alternate two operations. It was generated by the same engine that builds the IQ Octopus test, from a fixed seed, so it stays the same every time you visit. In the real test, items like this are generated fresh for every attempt.

New to this format? Read how to solve them, or time yourself on 10 in a row with the practice test.

25 puzzles · about 12 min

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