IQ sequence trap
Fast thinkers miss this
A quick number-sequence puzzle where the hidden rule rewards a second look.
Quick answer
Answer: 79
The rule is multiply by 2, then add 1. Four becomes 9, 9 becomes 19, 19 becomes 39, and 39 becomes 79.
How to use it
1
Test the simple gap pattern first.
2
Notice the gaps are not increasing evenly.
3
Try a repeatable operation.
4
Apply times 2 plus 1 to 39.
What this trains
Pattern recognition
Rule testing
Impulse control
Mental arithmetic
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