2017年8月1日SAT官方每日一题---数学.

　　为了同学们能够更好的复习SAT考试并加强习题锻炼，澳际留学小编每天会给大家整理一到SAT官网每日一题。今天，给小主们准备的是SAT数学真题，话不多说，赶紧看看吧。希望每天的坚持可以对同学们有所帮助。

　　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 end text of the 50% solution with y mL end text 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

　　答案：C

　　解析：

　　Choice C is correct. Since xmL of the 50% solution will be combined with ymL of the 25% solution to obtain 300mL of a 40% solution, it follows that x+y=300.

　　Since the pharmacist will mix xmL of the 50% solution and ymL of the 25% solution, the amount of actual medicine in the mixture is 0.5x+0.25y.

　　The doctor orders 300mL of the medicine at 40% solution. Which is (300)*(0.4)=120 milliliters of medicine.

　　Since the amount of actual medicine in the mixture must equal the amount of actual medicine in the end result, 0.5x+0.25y=120.

　　This all gives the following system of equations:

　　x+y=300

　　0.5x+0.25y=120

　　To find the value of x, eliminate y. Multiplying the first equation by -0.25 gives the following system:

　　-0.25x-0.25y=-75

　　0.5x+0.25y=120

　　Adding the two equations yields: 0.25x=45 And so x=180.

　　以上就是澳际留学小编今天给大家整理的2016年8月sat真题每日一练之数学真题，与大家共享，大家好才是真的好嘛。澳际留学小编希望每天坚持提供一道试题可以帮助同学们顺利通过考试。出国留学，澳际教育一直在!