已选分类
理学
单选题Inthemultiplicationproblemabove,F,G,andHrepresentuniqueodddigits.Whatisthevalueofthethree-digitnumberFGF?(A)151(B)161(C)171(D)313(E)353
单选题设事件A，B互不相容，则下列结论中，正确的是______。A．互不相容B．相容C．A，B相互独立D．P(A-B)=P(A)
单选题一元二次函数_f(x)=x(1-x)的最大值为( )． A．0.05 B．0.10 C．0.15 D．0.20 E．0.25
单选题The average (arithmetic mean) of five number is 26. After one of the numbers is removed, the average (arithmetic mean) of the remaining numbers is 25. What number has been removed?
单选题A square countertop has a square tile inlay in the center, leaving an untiled strip of uniform width around the tile. If the ratio of the tiled area to the untiled area is 25 to 39, which of the following could be the width, in inches, of tile strip? Ⅰ.1 Ⅱ.3 Ⅲ.4
单选题How many minutes will it take to completely fill a water tank with a capacity of 3,750 cubic feet if the water is being pumped into the tank at the rate of 800 cubic feet per minute and is being drained out of the tank at the rate of 300 cubic feet per minute? (A) 3 min. 36 see. (B) 6 minutes (C) 7 min. 30 sec. (D) 8 minutes (E) 1,875 minutes
单选题The arithmetic mean of a data set is 46 and the standard deviation of the set is 4. Which value is exactly 1.5 standard deviations from the arithmetic mean of the set? (A) 42 (B) 44.5 (C) 47.5 (D) 50 (E) 52
单选题设n阶矩阵A与B相似，且A+3E不可逆，则B的一个特征值为______。A．B．C．3D．-3
单选题等于多少?(1)XY=6(2)X+Y=5(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A clothing supplier stores 800 coats in a warehouse, of which 15 percent are full-length coats. If 500 of the shorter length coats are removed from the warehouse, what percent of the remaining coats are full length? (A) 5.62% (B) 9.37% (C)35% (D)40% (E) 48%
单选题SamandJessicaareinvitedtoadance.Ifthereare7menand7womenintotalatthedance,andonewomanandonemanarechosentoleadthedance,whatistheprobabilitythatSamandJessicawillNOTbechosentoleadthedance?
单选题If the width of a rectangle is increased by 25% while the length remains constant, the resulting area is what percent of the original area? (A) 25% (B) 75% (C) 125% (D) 225% (E) Cannot be determined from the information given.
单选题某百货商店的一种商品营业额为商品的售价乘以该商品的销售量。商品在促销期售价比上个月下降10%，该月销售量较上月增10%。问：促销月营业额较上月变化幅度。
单选题设有二维随机变量(X，Y)，已知D(X)=9，D(Y)=4；X，Y的相关系数为ρXY=，则D(X-2Y)=______。A.15B.17C.13D.5
单选题
单选题
单选题The enrollments at College X and College Y both grew by 8 percent from 1980 to 1985. If the enrollment at College X grew by 800 and the enrollment at College Y grew by 840, the enrollment at College Y was how much greater than the enrollment at College X in 1985?
单选题Together,AndreaandBrianweighppounds;Brianweighs10poundsmorethanAndrea.BrianandAndrea'sdog,Cubby,weighspoundsmorethanAndrea.Intermsofp.whatisCubby'sweightinpounds?
单选题某一直角坐标系中，有L1和L2两条直线，问L2是否过Ⅱ象限? (1)L1⊥L2 (2)L1过原点 (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．
单选题在某实验中，三个试管各盛水若干克．现将浓度为12%的盐水lO克倒入A管中，混合后取10克倒入B管中，混合后再取10克倒入C管中，结果A、B、C三个试管中盐水的浓度分别为6%、2%、0.5%，那么三个试管中原来盛水最多的试管及其盛水量各是( ). A．A试管，10克 B．B试管，20克 C．C试管，30克 D．B试管，40克 E．C试管，50克