Read the following SAT test question and then click on a button to select your answer.

A doctor orders 300 milliliters (mL) of a certain medicine at a 40% solution. The pharmacy has the medicine available only in 50% and 25% solution. The pharmacist will mix xmL of the 50% solution with ymL of the 25% solution to obtain the desired 40% solution. Which of the following is the value of x?

A.40
B.120
C.180
D.260

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