Quantitative Reasoning · Medium · 6 of 17
Number Series puzzle #6 (medium)
Which number comes next? Tap an option to check your answer, or show the answer for the step-by-step solution. Rule in play: two interleaved series.
Plate 06 / 17 · Medium
Which number comes next?
13, 21, 18, 19, 23, ?
Tap the option you think is right, or show the answer.
Show the answer
The next number is 17 (option 3).
How to solve it
- The gaps jump around, so look at every other number.
- The 1st, 3rd, 5th numbers (13, 18, 23) go up by 5 each time.
- The 2nd, 4th, 6th numbers (21, 19) go down by 2 each time.
- The missing number continues the second series: 19 - 2 = 17.
About this puzzle
Medium series use gaps that grow, square numbers, or two series taking turns. 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.
Related
- No. 01Medium number series17 medium puzzles with answers and worked solutions.
- No. 02Number Series puzzles50 puzzles, easy to hard. Which number comes next?
- No. 03Number sequence testTen number series, 30 seconds each. Find the rule.
- No. 04Number seriesThe rules behind number series, and a method that finds them.
25 puzzles · about 12 min
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