已选分类
理学数学
单选题One set of numbers consists of consecutive integers and the least number is 3.How many numbers are there in the set? (1)The average of all the numbers in the set is 6; (2)The number of integers is one more than the range of the set.
单选题设，则______．
单选题Inacertainflowershop,whichstocksfourtypesofflowers,thereareasmanyvioletsascarnations,andasmanytulipsasviolets.Ifthereareequalnumbersofrosesandtulips,whatpercentoftheflowersintheshoparecarnations?
单选题If the areas of the three different sized faces of a rectangular solid are 6, 8, and 12, then what is the volume of the solid? (A) 576 (B) 288 (C) 144 (D) 48 (E) 24
单选题
单选题Joe works two part time jobs. One week Joe worked 8 hours at one job, earning $150, and 4.5 hours at other job, earning $90. What were his average hourly earnings for the week? (A) $8.00 (B) $9.60 (C) $16.00 (D) $19.20 (E) $32.00
单选题The product of three consecutive integers must be Ⅰ. Divisible by 3 Ⅱ. Divisible by 5 Ⅲ. Divisible by 6 (A) Ⅰ only (B) Ⅱ only (C) Ⅰand Ⅱ only (D) Ⅰ and Ⅲ only (E) Ⅰ, Ⅱ, and Ⅲ
单选题X，Y为正整数，X是否可被3整除? (1)(X-Y)可被3整除 (2)(X-2Y)可被3整除
单选题MachinesAandBalwaysoperateindependentlyandattheirrespectiveconstantrates.Whenworkingalone,machineAcanfillaproductionlotin5hours,andmachineBcanfillthesamelotinxhours.Whenthetwomachinesoperatesimultaneouslytofilltheproductionlot,ittakesthem2hourstocompletethejob.Whatisthevalueofx?
单选题设函数f(x，y)连续，交换二次积分次序得=______。A．B．C．D．
单选题3, k, 2, 8, m, 3 The arithmetic mean of the list of numbers above is 4. If k and m are integers and k≠m, what is the median of the list? (A) 2 (B) 2.5 (C) 3 (D) 3.5 (E) 4
单选题若圆C:(x+1)2+(y-1)2=1与x轴切于A点、与Y轴切于B点．则与此圆相切于劣弧中点M(注：小于半圆的弧称为劣弧)的切线方程是()．
单选题A prize of $240 is divided between two persons. If one person receives $180, then what is the difference between the amounts received by the persons? (A) $30 (B) $60 (C) $120 (D) $210 (E) $420
单选题已知向量组α1，α2，α3线性无关，则下列向量组中线性无关的是______。
A.α1+2α2，2α2+α3，α3-α1
B.α1-2α2，α2-α3，2α3-α1
C.2α1-α2，α2+2α3，α3-α1
D.α1-α2，α2+2α3，2α3+α1
单选题直线L通过(1, q)，问其斜率(slope)是否大于0? (1)该直线通过(q, 1) (2)该直线通过(13, q) (A) 条件(1)充分，但条件(2)不充分． (B) 条件(2)充分，但条件(1)不充分． (C) 条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分． (D) 条件(1)充分，条件(2)也充分． (E) 条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．
单选题
单选题设函数，则f(x)______。A.有1个无穷间断点B.有2个无穷间断点C.有1个跳跃间断点D.有3个可去间断点
单选题已知an是等差数列，则下列不等式成立的是______． A．a3a6＞a4a5 B．a3a6≥a4a5 C．a3a6＜a4a5 D．a3a6≤a4a5
单选题A salesman makes a profit of 25% on all sales. How many fax machines will he have to sell for $375 each to make a total commission of at least $ 500? (A) 4 (B) 5 (C) 6 (D) 15 (E) 20
单选题湖中有四个小岛，它们的位置恰好近似构成正方形的四个顶点．若要修建三座桥将这四个小岛连接起来，则不同的建桥方案有( )种． A．12 B．16 C．18 D．20 E．24