gwd1里的几道数学，原来连接帖里没有找到对应题目

qianyexia

 

谢谢各位先，我去gwd讨论帖查了，跟gwd-24里的题怎么都对不上啊。。。。郁闷

如果有连接的话，就麻烦再帖个连接吧。实在是题号对不上才麻烦大家的。。。。。

Q2:

A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.  If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?

 

A.        0

B.        1/9

C.        2/9

D.       1/3

E.        1

题目不太理解

Q9:

A gardener is going to plant 2 red rosebushes and 2 white rosebushes.  If the gardener is to select each of the bushes at random, one at a time, and plant them in a row, what is the probability that the 2 rosebushes in the middle of the row will be the red rosebushes?

 

A.      1/12

B.      1/6

C.      1/5

D.     1/3

E.      1/2

Q17:

In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.  What percent of the employed people in Town X are females?

 

A.      16%

B.      25%

C.      32%

D.     40%

E.      52%

我怎么算出来都是A呢。。。。

Q19:

A total of $60,000 was invested for one year.  But of this amount earned simple annual interest at the rate of x percent per year, and the rest earned simple annual interest at the rate of y percent per year.  If the total interest earned by the $60,000 for that year was $4,080, what is the value of x?

(1)     x = (3/4) y

(2)   The ratio of the amount that earned interest at the rate of x percent per year to the amount that earned interest at the rate of y percent per year was 3 to 2.

为什么存一年，有rest amount？题没读太懂。。。。

Q30:

Joanna bought only $0.15 stamps and $0.29 stamps.  How many $0.15 stamps did she buy?

(1)     She bought $4.40 worth of stamps.

(2)     She bought an equal number of $0.15 stamps and $0.29 stamps.

2为什么是对的呢？