(修复的)管卫东讲解GWD考题.docx

When positive integer x is divided by positive integer y, the remainder is 9. If x/y = 96.12, what is the value of y?96 75 48 25 12 X=(96+0.12)Y0.12Y=9Y=75The figure above shows the dimensions of a semicircular cross section of a one-way tunnel. The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel. If vehicles must near the top of the tunnel by at least ? foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?5? ft 7? ft 8 ? ft 9? ft 10 ft 理解问题：要画图：单的轨道是12feet而且等距，半圆形隧道里面还有一个长方形的轨道，从圆心开始从左从句开始延展6，以圆心垂直于半径为对称轴向上做垂线，由于大圆半径是10，所以高是8，车要低于0.5米，所以是7.5米，关键是那句话怎么理解。The operation ? is defined for all nonzero numbers a and b by a ? b = a/b – b/a.? If x and y are nonzero numbers, which of the following statements must be true?I.????????????????? x ? xy = x(1 ? y)II.???????????????? x ? y = -(y ? x)III.?????????????? 1/x ? 1/y = y ? x?I only II only III only I and II II and III x ? xy = x(1 ? y)左=X/XY-XY/X=1/Y-Y右=X（1/Y-Y/1),X消不掉，因此两边不等II. x ? y = -(y ? x) 成立III. 1/x ? 1/y = y ? x 成立后面懒得再做了，就是把握a ? b = a/b – b/a这样的定义，代入化简变形即可，选E 把xy当成整体来做If a and b are positive, is less than?(1)?? ? a = 2b(2)?? ? a + b 1Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient. EACH statement ALONE is sufficient. Statements (1) and (2) TOGETHER are NOT sufficient. 第一式 = ab/(a+b)第二式 = ab/1a、b 为正数 1)第一式 = 2b/3第二式 = 2b*b无法比较两式大小2）a + b 1 so 1/(a+b) 1/1soab/(a+b) ab/1可判断大小两式大小A construction company was paid a total of $500,000 for a construction project. The companys only costs for the project were for labor and materials. Was the companys profit for the project greater than $150,000?(1) The companys total cost was three times its cost for materials.TC=3MC，LC=2MC，条件不够(2) The companys profit was greater than