Small leverage words here make a big difference. First, notice that the "total" cost of 300 stocks is equal to \(m\). Thus, the cost
per stock would be \(\frac{m}{300}\). This fraction matches answer choice (B), and highlights a classic trap of the GMAT: answer choices often include the "right answer to the wrong question." The target of this question is not the original cost per stock, but instead the price at which each stock was sold,
after an increase.
The question indicates that each share was sold at 50% above the original cost. This is a percentage increase, adding half of the original value to the value. Thus, if the original cost per stock were \((\frac{m}{300})\), the value of the stock after the increase would be \((\frac{m}{300})(1+\frac{1}{2})\). Now, don't convert the fraction to decimal values here. Not only are "fractions your friends", but the answer choices clearly keep the math in fractional form.
Now, we need to just simplify the math, looking for common factors in the top and bottom of the equation to make the math even easier:
\((\frac{m}{300})(1+\frac{1}{2})=(\frac{m}{3*100})(\frac{3}{2})=\frac{m}{200}\)
The answer is (C).
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Aaron J. PondVeritas Prep Elite-Level InstructorHit "+1 Kudos" if my post helped you understand the GMAT better.
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