prep中几道数学题目请教[没问过]

A company plans to assign identification numbers to its employees.  Each number is to consist of four different digits from 0 to 9, inclusive, except that the first digit cannot be 0.  How many different identification numbers are possible?

(A) 3,024

(B) 4,536

(C) 5,040

(D) 9,000

(E) 10,000

答案: B

96.   10591-!-item-!-187;#058&007292

According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make orange juice.  How many 12-ounce cans of the concentrate are required to prepare 200 6-ounce servings of orange juice?

(A)  25

(B)  34

(C)  50

(D)  67

(E)  100

答案: A

这题题目不很明白，麻烦解释下

98.   10689-!-item-!-187;#058&007329

If x is a negative integer, which of the following expressions has the LEAST value?

(A) x2 - 0.50

(B) x2 - 0.51

(C) x3 - 0.502

(D) x3 - 0.511

(E) x4 - 0.512

答案: D

这题感觉答案错了，我选E

请教大家，谢谢！

94

分两种情况：（1）4个数中没有0 有A(4,9)种 （2）有0 有C(3,9)*3*3*2*1种

两种情况加起来即可

95

 200 6-ounce 是指200听 每听6盎司 这个理解了应该清楚拉把

96

x为负数，所以应该为奇数次方

谢谢

第一题:我没看清楚一个条件，four different digits ，我之前以为可以相同.其实直接9*9*8*7就能得出结果了

第二题:明白了

第三题:估计这题没有写清楚，如果是次方，应该x^3表示，x3我就认为是乘了