Multiple choice

Identify the missing numeric variable value from the sequence track below: 12, 48, 120, 24, 36, 18, 54, 126, 27, 39, ?, 15, 135, 25, 45

  1. 30

  2. 40

  3. 45

  4. 50

  5. 60
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A Correct answer
Explanation

The sequence follows a pattern of alternating operations: 12*4=48, 48+72=120, 120/5=24, 24+12=36, 36/2=18, 18*3=54, 54+72=126, 126/4.6... The pattern is actually three interleaved sequences: (12, 24, 27, ?), (48, 36, 39, 15), (120, 18, 54, 126, 135, 25, 45). A simpler view is groups of three: (12, 48, 120), (24, 36, 18), (54, 126, 27), (39, ?, 15). The missing number is 30.

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