下面GMAT思為大家整理了GMAT數學備考資料：練習+講解（1），供考生們參考，以下是詳細內容。
16、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. Whats the largest possible number of respondents favoring C, but not C B, nor C A.
【答案】12000.28=336
【思路】題目問只選C的最大可能數是多少，要使這個數最大，就要滿足所有選C的人，都不會同時選A或者B。即P=1-P=1-=1-=0.28。
17、A plane flied a distance of 800 miles at 360m/h with wind speed. And flied back at 260m/h with wind against it. Whats the average speed of the round-trip?
【答案】約等於302m/h
【思路】將題目理解為單程800m，round-trip 1600m，兩個時速中已計入風速的影響，不另行計算。則第一段距離800m，時速360m/h，用時20/9h;第二段距離800m，時速260m/h，用時40/13h。則全程的'平均時速=1600/=9360/31,約等於302m/h。
18、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?
x = 12m/h
y = 20m/h
【答案】選c
【思路】根據題意，應該為y = 20m。只有將和的條件合在一起，同時知道兩段路程的長度分配和每段路程的速度，此題才有確定的解。
