Which number replaces the question mark?
A.
9
B.
6
C.
3
D.
12
Correct answer is C
In each diagram, the numerical value of the left hand letter equals the product of the upper and lower left hand numbers, and the right hand letter equals the product of the upper and lower right hand numbers. The numerical value of the central letter equals the sum of the numerical values of the left and right hand letters.
