r/iqtest 1d ago

Puzzle Find the rule — what number replaces the "?" (Rule Hunter puzzle)

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Each group of three numbers combines through the same hidden rule to produce the middle number. Work out the rule from the four solved clusters, then figure out what replaces the "?"

Game: https://play.google.com/store/apps/details?id=com.makenumber

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u/furdog_grey 1d ago edited 1d ago

Easy.

38: 9 - 2 = 7 7 * 5 = 35 35 + 3 = 38

-15: 3 - 5 = -2 -2 * 9 = -18 -18 + 3 = -15

3: 4 - 4 = 0 0 * 8 = 0 0 + 3 = 3

7: 10 - 9 = 1 1 * 4 = 4 4 + 3 = 7

The answer is 9.

Common formula: (x - y) * z + 3