1.If a motorist had driven 1 hour longer n a certain day and at an average rate of 5 miles per hour faster, he would have covered 70 more miles than he actually did.How many more miles would he have covered than he actually did if he had driven 2 hour longer and at an average rate of 10 miles per hour faster on that day?
A 100 B 120 C 140 D 150 E can not be determined
答案是E，但是我的结果是D
方程为（T+1）(V+5)=TV+70 TV+5T+V+5=TV+70 5T+V=65
(T+2)(V+10)=TV+10T+2V+20=TV+150
2.On a certain day it took Bill three times as long to drive from home to work as it took Sue to drive from home to work.How many kilometres did Bill drive from home to work?
(1)Sue drove 10 kilometers from home to work,and the ratio of distance driven from home to work time to drive from home to work was the same for Bill and Sue
(2)The ratio of distance driven from home to work tme to drive from home to work time to drive from home to work for Sue that day was 64 kilometers per hour
这道题的答案我读不太懂，请大家指教
3.抽签口试，共有a+b张考签，每个考生抽一张考签，抽过的不再放回，考生王某会答其中a张，他是第k个抽签者k<=(a+b)，求王某抽到会答考签的概率。
答案是p=a/(a+b)
我觉得这个答案是在放回抽取的情况下计算出来的，但是题目中说明了是不放回抽取啊
4.If ? represents a digit in the 7-digit number 362?215,what is the value of ?
(1)The sum of the 7 digits is equal to 4 times an integer
(2)The missing digit is different from any of the other digits in the number
答案是E，但是根据（1）（2）应该得出？＝9啊
5.5辆车排成一排，1辆黄色，1辆蓝色，3辆红色，且3辆红车不可分辨，问有多少种排法？
答案是P55/P33，我不太清楚怎么得出来的，我感觉应该是P55-P33-P44
6.某种硬币每掷一次正面朝上的几率为0.6，问连续地抛5次，至少有4次朝上的几率？
答案是（0.6）2＋C54X(0.6)4X0.4
但是我觉得答案应该只是C54X(0.6)4X0.4，前面的（0.6）2是什么意思呢（0.6的平方）
7.三个人独立去破译一个密码，他们能译出的概率分别为1/5，1/3，1/4，求将此密码译出的概率？
8.The surface area of a square tabletop was changed so that one of the dimensions was reduced by 1inches and the oter dimension was increased by 2 inches.What was the surface area before these changes were made?
(1)After the changes were made,the surface area was 70 square inches.
(2)There was a 25 percent increase in one of the dimension.
答案是D,我选的E，因为我觉得题目种的各个dimension都没有明确的指代
9.The number of diagonals of a polygon of n sides is given by the formula d=n(n-3).If a polygon has twice as many diagonals as sides,how many sides does it have?
A.3 B.5 C.6 D.7 E.8
答案是C,我选B
10.What is the greatest possible length of a positive integer less than 1000?
length 在这里是什么意思呢？ | 
