Hi All,
This is an example of a "symbolism" question - it involves a "made up" math symbol which you'll be asked to use to perform a basic set of calculations. You'll likely see 1 such question on the GMAT and it almost always involves some type of arithmetic or algebra.
We're told that the symbol # is one of 4 possible math functions: add, subtract, multiply, or divide.
We're asked if (A+B)#C = (A#C) + (B#C) for all numbers A, B, and C? This is a YES/NO question. The answer will depend on the actual 'meaning' of the symbol.
In these types of questions, it might be tempting to do a lot of pre-work before dealing with the two Facts. However, much of that work is NOT necessary, so in this case it would be a waste of time.
Fact 1: 1#C = C#1
This means that the symbol can be 1 of 2 possibilities: either 'add' or 'multiply'
Let's TEST VALUES to see what happens in each case:
IF.....
A=1
B=2
C=3
# means 'add'
(A+B)#C = (A#C) + (B#C) =
(1+2)+3 = (1+3) + (2+3)?
6 = 4 + 5?
The answer to the question is NO.
IF...# means 'multiply'
(A+B)#C = (A#C) + (B#C) =
(1+2)(3) = (1)(3) + (2)(3)?
9 = 3 + 6?
The answer to the question is YES.
Fact 1 is INSUFFICIENT
Fact 2: # represents "+"
Since we know the symbol can only represent one symbol, then we CAN answer the question.
Fact 2 is SUFFICIENT.
Final Answer:
GMAT assassins aren't born, they're made,
Rich