例:The average(arithmetic mean)of the 11 numbers in a list is 14. If the average of 9 of the numbers in the list is 9,what is the average of the other 2 numbers(11个数的算术平均数是14。若其中9个数的算术平均数为9,则剩下的2个数的平均数是多少
例:The symbol represents one of the four operations of addition, subtraction, multiplication, and division, and 3 1 = 3.
For each of the following equations, indicate whether the equation must be true, must be false, or could be either true or false.
Equation
Must Be True
Must Be False
Could Be True or False
6 2 = 3
6 2 = 4
6 2 = 12
Click on your choices.
Click on the answer box, then type in a number. Backspace to erase.
GRE中出现的非常规数学符号可以看成ETS自己定义的一种运算。本题中,符号“”代表的是加减乘除四种四则运算中的某一种,而且31=3,由这些已知条件可以推出可以是,也可以不是。接下来就考察考生对于must be true、could be true这类逻辑判断语言的理解了。Must be true意为必然正确,在任何时候都不可违背;Could be true意为可以正确,即存在正确的可能。
因此第一个等式62=3在代表除时错误,但在代表加、减、乘时正确,因此第一式应为could be true or false有可能对也可能错;