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25. What number should replace the question mark?
  IQ test. Accurate and free online iq test # 4 with answers and solutions. Question # 25. What number should replace the question mark?
 

Explanation:
The number in the third row = (the number in the first row is multiplied by the number of the second row) + 2 to the power of the column number. (16 = 2 × 7 + 2; 31 = 3 × 9 + 4; 48 = 5 × 8 + 8; 71 = 5 × 11 + 16).