单选题Rolling a number cube with faces numbered 1 to 6 similar to a 6-sided die is an experiment with 6 possible outcomes: 1, 2, 3, 4, 5 or 6. If we toss two number cubes simultaneously, what is the possibl
单选题共有A，B，C，D，E 5个元素要放在有顺序的5个位置上，要求满足条件：A在B之前，B在C之前A＞B＞C，同时还要满足D在E的前面D＞E，问一共有多少种排法?
单选题Which of the following cannot be expressed as the sum of two prime numbers?
单选题1．234 1．243 1．324 . . . . . . +4．321 The addition problem above shows four of the 24 different integers that can be formed by using each of the digits 1，2，3，and 4 exactly once in each integer． What is
单选题If x is a prime number, what is the value of x?141＜x＜482x+1 is a multiple of 4.
单选题If two liters of a solution that is 15 percent salt will be added to 5 liters of a solution that is 8 percent salt, what percent salt will the resulting solution contain?
单选题A rope 60 meters long is cut into three pieces A, B, C, If piece A is 12 meters longer than piece B, piece B is 9 meters shorter than piece C, then what is the length, in meters, of the shortest piece
单选题两个质数的和是40，求这两个质数的乘积的最大值是多少?
单选题求1～100中既不是5的倍数，又不是6的倍数的数有多少个?
单选题Two keys are to be put into the key chain that already has 5 keys. What is the probability that these two keys will be next to each other?
单选题从南京经过上海再到广州，南京到上海有3种方法，轮船、火车、飞机；上海到广州有2种方法，火车、飞机，则共有多少种方法?
单选题Five pairs of socks are of different color. If two socks are to be selected at random, what is the probability that the two socks will be one pair?
单选题On May first, in order to reduce the number of
单选题The ratio of girls to boys in a class is 3 to 4. If there are a total of 28 students in the class, how many girls are there?
单选题某一个公司的所有电话分机都是偶数.如果每一个分机号都是由5个数字1，3，4，5，6组成，那么这个公司最多能够有多少个五位分机号码?
单选题A triangle has one side of length 5 and another side of length 14. What are the greatest and least possible integer values for the length of remaining side?
单选题If z1 z2, z3…zn is a series of consecutive positive integers, is the sum of all these integers odd?1z1+z2+z3+…+znn is an odd integer.2n is odd.
单选题The letters C, I, R, C, L, and E can be used to form 6-letter strings such as CIRCLE or CCIRLE. Using these letters, how many different 6-letter strings can be formed in which the two occurrences of t