题海战术是GMAT考试考生们经常用的方法，比较常见的就是在
1、There are 1200 respondents to a poll, each favoring their preference for candidates A, B, and C. 54% favored A, 48% favored B, and 42% favored C, and there is 30% favored both A and B. What’s the largest possible number of respondents favoring C, but not C & B, nor C &A.
【答案】1200×0.28=336
【思路】题目问只选C的最大可能数是多少，要使这个数最大，就要满足所有选C的人，都不会同时选A或者B。即P(c)=1-P(A+B)=1-[P(A)+P(B)-P(AB)]=1-(0.54+0.48-0.3)=0.28。
2、A plane flied a distance of 800 miles at 360m/h with wind speed. And flied back at 260m/h with wind against it. What’s the average speed of the round-trip?
【答案】约等于302m/h
【思路】将题目理解为单程800m，round-trip 1600m，两个时速中已计入风速的影响，不另行计算。则第一段距离800m，时速360m/h，用时20/9h;第二段距离800m，时速260m/h，用时40/13h。则全程的平均时速=1600/(20/9+40/13)=9360/31,约等于302m/h。
3、To travel trip of 40 miles… the speed for the first Y miles was X, and the speed for the remaining 40-y is 1.2X. What average speed?
(1) x = 12m/h
(2) y = 20m/h
【答案】选c
【思路】根据题意，(2)应该为y = 20m。只有将(1)和(2)的条件合在一起，同时知道两段路程的长度分配和每段路程的速度，此题才有确定的解。