Civil Service Exam Reviewer · Number Series · hard

What number(s) should complete the series: 7, 21, 16, 48, 43, 129, ?

  1. 124
  2. 387
  3. 119
  4. 172

Answer

A. 124

Solution

Alternately multiply by 3 and subtract 5: the next step is a subtraction, 129 − 5 = 124.

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