麻烦牛牛解题!! PS&DS

wanlingH

 

请教几题
                            Q:

PS:

1.Pipe P can drain the liquid from tank in 3/4 the time that it takes Pipe Q to drain it and in 2/3 the time that it takes Pipe R to it. If all three pipes operating stimulatory but independently are used to drains liquid from the tank , then the Pipe Q drains what portion of the liquid form the tank ?

 

Answer: 9/29

 

题目绕绕的看不太懂~ 虽然我做对了
                                    > <

请牛牛解释一下

 

2. On a soccer team of 21 children, some of which are boy and some of which are girls, exactly 2/3 of the boys and exactly 1/3 of the girls attended the end of the season pizza party. What is the greatest number of children on the team who could have attended the party distance?

(1) 11   (2)12  (3) 13  (4)14  (5) 15

Answer: 13

 

这题怎么解阿  我觉得问题应该是卡在exactly 上

 

3. the usable portion of a certain tree trunk is a perfect right cylinder 8/ 3.1415.. inches tall with a radius of 10 inches . If a given volume of wood makes an equal volume of paper, and ream(stack) of 500 sheets of 8.5”×11”of paper is 2 inches tall.

How many full reams of paper can be made out of this particular tree?

(1)3  (2)4  (3)5  (4)8  (5) 9

 

这这这…题在做什么
                                阿
                                ? ?

 

DS:

1.What would it cost to put a fence around a rectangle field, if the cost of fencing is ＄2.5?

 

(1) the combined length and width of the field is 1200 feet

 

(2) if the length of the field was twice as long as it is now, it would cost ＄10,500 to fence the field

 

Answer: A

 

我的问题在于
                                (1) 我只知道
                                2(width+length)=1200

              我怎么会知道
                                他的cost??

             (2) (2length+width)2= ＄10500

 

应该要结合条件2  才可以阿??

 

麻烦牛牛解题!!
                                    

 

 

机考的数学现在都偏向题目很绕吗??

 

请教几题
                Q:

PS:

1.Pipe P can drain the liquid from tank in 3/4 the time that it takes Pipe Q to drain it and in 2/3 the time that it takes Pipe R to it. If all three pipes operating stimulatory but independently are used to drains liquid from the tank , then the Pipe Q drains what portion of the liquid form the tank ?

 

Answer: 9/29

 

题目绕绕的看不太懂~ 虽然我做对了
                        > <

请牛牛解释一下

 

2. On a soccer team of 21 children, some of which are boy and some of which are girls, exactly 2/3 of the boys and exactly 1/3 of the girls attended the end of the season pizza party. What is the greatest number of children on the team who could have attended the party distance?

(1) 11   (2)12  (3) 13  (4)14  (5) 15

Answer: 13

 

这题怎么解阿  我觉得问题应该是卡在exactly 上

 

3. the usable portion of a certain tree trunk is a perfect right cylinder 8/ 3.1415.. inches tall with a radius of 10 inches . If a given volume of wood makes an equal volume of paper, and ream(stack) of 500 sheets of 8.5”×11”of paper is 2 inches tall.

How many full reams of paper can be made out of this particular tree?

(1)3  (2)4  (3)5  (4)8  (5) 9

 

这这这…题在做什么
                    阿
                    ? ?

 

DS:

1.What would it cost to put a fence around a rectangle field, if the cost of fencing is ＄2.5?

 

(1) the combined length and width of the field is 1200 feet

 

(2) if the length of the field was twice as long as it is now, it would cost ＄10,500 to fence the field

 

Answer: A

 

我的问题在于
                    (1) 我只知道
                    2(width+length)=1200

              我怎么会知道
                    他的cost??

             (2) (2length+width)2= ＄10500

 

应该要结合条件2  才可以阿??

 

麻烦牛牛解题!!
                        

 

 

机考的数学现在都偏向题目很绕吗??

lyjranchel

第二题  who could have attended the party distance?   是什么意思哦？

wanlingH

Ding

help to resolve these question!

gpc7109

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

哪位同学可以帮忙解答？！为什么答案是Ｅ不是Ｂ．

ghgriffin

以下是引用gpc7109在2009-5-12 21:50:00的发言：

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

哪位同学可以帮忙解答？！为什么答案是Ｅ不是Ｂ．

答案应该是C

每一次乘车都有三种可能性，则共有3*3*3=27种可能性

三台车都要坐的话有顺序问题，有六种顺序，所以答案为2/9