I suspect that the question stem should read as follows:
NDroho wrote:What is the value of (2^x + 2^x)/(2^y)?
1) x - y = 8
2) x/y = -3
2^x + 2^x means that we have TWO values of 2^x:
2 * 2^x.
When we MULTIPLY two values with the same base, we ADD the exponents:
2¹ * 2^x = 2^(1+x).
At this point, the question stem can be rephrased as follows:
What is the value of 2^(1+x) / 2^y?
When we DIVIDE two values with the same base, we SUBTRACT the exponents:
2^(1+x) / 2^y = 2^(1+x-y).
To determine the value of 2^(1+x-y), we need to know the value of x-y.
Final rephrase:
What is the value of x-y?
Statement 1: x-y = 8.
SUFFICIENT.
Statement 2: x/y = -3
x = -3y
x + 3y = 0.
No way to determine the value of x-y.
INSUFFICIENT.
The correct answer is
A.
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