There are 8 books on a shelf, of which 2 are paperbacks and6 are hardbacks. How many possibleselections of 4 books from this self include at least one paperback?
A. 40
B. 45
C. 50
D. 55
E. 60
参考答案：D
题目翻译：8本书，2本纸封，6本硬封。选四本至少一本纸封的选法几种。
题目全解：总的选法-全都是硬封=至少一本纸封=C(4,8)-C(4,6)=55。
A certain roller coaster has 3 cars, and a passenger isequally likely to ride in any 1 of the 3 cars each time that passenger ridesthe roller coaster. If a certainpassenger is to ride the roller coaster 3 times, what is the probability thatthe passenger will ride in each of the 3 cars?
A. 0
B. 1/9
C. 2/9
D. 1/3
E. 1
参考答案：C
题目翻译：三个车，一个乘客每次随便挑一个坐。做了三次，求三次都不同一车的概率。
题目全解：1*(2/3)*(1/3)=2/9。
The value of (9*10^7)(9*10^8)is closest to which of the following?
A. 10^16
B. 10^17
C. 10^56
D. 10^57
E. 10^58
参考答案：B
题目翻译：(9*10^7)(9*10^8)和那个最接近
题目全解：
等式=81*10^15约等于100*10^15。
| GMAT数学练习题及答案解析小结 |