5
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Which of the 5 answers fits the grid, and what is the pattern?

? 4 2
5 ? 9
6 12 ?
  • A. 13-21-18
  • B. 10-18-19
  • C. 12-20-19
  • D. 11-22-15
  • E. 19-19-19

Original image found on Reddit

The answer is given as C, but no explanation is given as to why C is correct.

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2
  • 1
    $\begingroup$ Do the dashes between the numbers just separate the numbers or denote negatives for the second two digits? $\endgroup$
    – Area 51
    Jun 20, 2021 at 16:31
  • $\begingroup$ I believe they just separate the numbers. $\endgroup$
    – TimS
    Jun 20, 2021 at 23:37

1 Answer 1

3
+50
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I tried various techniques, but only this seemed to make any sense to me

Each number should be written as the number of prime factors it has. This number is [1,2,3] in each row.

eg -> 5 has only 1 prime factor '5'. So replace 5 with 1. 12 has 3 prime factors (2,2,3). So replace 12 with 3. And so on.

Using this logic, we see that we need a number with 3 prime factors in first and second row and number with 1 prime factor in last row. Only 'c' satisfies our criteria

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