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
单选题The surface distance between 2 points on the surface of a cube is the length of the shortest path on the surface of the cube that joins the 2 points．If a cube has edges of length 4 centimeters，what is
单选题Town X has 50,000 residents, some of whom were born in Town X. What percent of the residents of Town X were born in Town X ?1 Of the male residents of Town X, 40 percent were not born in Town X. 2 Of
单选题When 25 is divided by the positive integer m, the remainder is m-5. Which of the following could be the value of m?
单选题What’s the median of 3，6，5，1，6，7，8?
单选题一列火车A早晨6点从甲地开往乙地，速度为45千米小时，另一列火车B在2个小时后从乙地开往甲地，速度比A快15千米小时，中午12时两车同时经过途中某站丙地，然后再继续前进，问B到达甲地时，A离乙地还有多远?
单选题In a rectangular coordinate system, the set of all points x, y such that x2+y2＜1 comprises
单选题如果M和N被6除得到的余数分别为3和5，那么下面哪一个不可能为M+N的值?
单选题数列{a1，a2，…，an，…}，a1=5，a2=10，an+1=anaan-1，问第几项起就至少有5百万位数字?