This data sufficiency question asks the following: "What fractional part of the total surface area of cube C is red?"
(1) Each of 3 faces of C is exactly 1/2 red.
(2) Each of 3 faces of C is entirely white.The correct answer is C
, because you need both information to conclusively answer the question. I chose answer A
because I felt that the first statement was sufficient to answer the question about the fraction of cube C's surface area being red. Is my error an example of a technique mentioned in the Data Sufficiency chapter