Explanation

　　1.The correct answer is A

　　If X stands for the tens digit, then 3X stands for the hundreds digit and 2X stands for the units digit. Since the sum of the digits is 12,3X+X+2X=12. Solving this gives X=2.

　　2.The correct answer is A

　　If the 100 integers are ordered from least to greatest, the median, M, is found by taking the average of the 50th and 51st numbers in the ordered list. Suppose the list of integers is . Then the average, a, of the integers is , and the median, m, is equal to 0. So , and the list satisfies the conditions given in the question. For this list, 1 term is greater than a, and 99 terms are less thana , so statement I is not true. Also,1 term is greater than m, and 1 term is less than m, so neither statement II nor statement III is true. Thus, for this list, none of the given statements is true. Therefore, the correct answer is choice (A), none of the statements must be true.

　　3.The correct answer is A

　　Drawing the vertical line "Number of Items = 10" and the horizontal line "Total Cost = "$20" divides the scatterplot into four regions, as shown in the figure below.

　　The lower right region lies below the line "Total Cost = $20" and to the right of the line "Number of Items = 10." Thus the points in this region are exactly the points that represent a purchase of more than 10 items at a total cost of less than $20. (Note the that points on the line "Number of Items = 10" represent a purchase of exactly 10 items, not more than 10 items and, thus, do not meet the given conditions.) There are four points in the lower right region. Therefore, four of the customers bought more than 10 items and spent less than $20.

　　4.The correct answer is A

　　Recall that 0.06 percent means 0.06 out of every 100, or 6 out of every 10000. The question asks for an equivalent ratio: 3 out of how many. The ratio 6 out of 10000 can be reduced (by dividing both members by 2) to 3 out of 5000.

　　5.The correct answer is B

　　If two lines are perpendicular, the product of their slopes is equal to -1. The function F(x)=5x-2 is in slope-intercept form, so the slope of the graph of F(x)=5x-2 is equal to 5. Therefore, the slope of line 1 must be equal to -1/5. The only choice that corresponds to a slope of -1/5 is g(x)=-1/5x.

　6.The correct answer is C

　　Suppose that x quarts of the final mixture of dye will be made. Since it is to be made from equal amounts of orange and green dye, it will consist of 1/2 x quarts of orange dye and 1/2 x quarts of green dye. Since the orange dye has 2 parts yellow dye for each 5 parts total dye,2/5 of it is yellow dye. Similarly,1/3 of the green dye is yellow dye. The amount of yellow in the final mixture is given by

　　So 11/30 of the final mixture is yellow dye.

　　Note: Although “quarts” were used to express the amount of the final mixture, it could have been pints or any other unit of liquid measure.

　　7.The correct answer is B

　　When the speed of a train in miles per hour is multiplied by the travel time in hours, the distance traveled by the train is obtained. The distance that the first train travels is 60 miles per hour times 1 hour, which is 60 miles. Using the variable x for the travel time, in hours, of the second train, the distance that the second train travels is 30 miles per hour times x hours, which is 30x miles. Since the two trains travel the same distance, 60=30x, which gives x=2 hours, the travel time of the second train.

　　以上就是这7道SAT数学练习题目的全部内容，非常详细。天道小编建议大家在备考这些SAT数学题目的时候，可以根据答案和自己答题的实际情况，对数学方面的知识点和相关词汇进行更加有针对性的准备，就能更好的应对考试了。