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10. What figure should replace the question mark?
  IQ test. Free iq test online # 1 with answers and solutions. Question # 10. What figure should replace the question mark?
 

Explanation:
The numbers inside the circle are added together. The numbers outside the circle are subtracted. The total amount is inside the triangle. (5 + 17 + 24 - 3 - 9 - 18 = 16; 7 + 15 + 35 - 8 - 14 - 23 = 12; 14 + 23 + 45 - 7 - 26 - 39 = 10).