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标题: [求助]PREP模考2的几道奇怪的数学题~ [打印本页]

作者: 冰岛哲学C 时间: 2007-12-9 20:10
标题: [求助]PREP模考2的几道奇怪的数学题~

1.What is the average (arithmetic mean) height of the n people in a certain group?

DS的题目.

选项

the sum of the heights of the n people is 178 feet 9 inches.

为什么这个选项是不充分的啊? 我觉得这不是大白话嘛..知总数.除一下不就能得平均了么?为什么不充分啊???

The table above shows the total sales recorded in July for the 5 salespeople at Acme Truck Sales. It was discovered that one of Cal's sales was incorrectly recorded as one of Ann's sales. After this error was corrected, Ann's total sales were still higher than Cal's total sales, and the median of the 5 sales totals was $330,000. What was the value of the incorrectly recorded sale?

table: Ann $450,000

Bob $360,000

Cal $190,000

Dot $210,000

Ed $680,000

答案选的是 120,000

怎么都没搞懂这题什么意思。.大家给解答下吧~`

table: Ann $450,000

Bob $360,000

Cal $190,000

Dot $210,000

Ed $680,000

答案选的是 120,000

怎么都没搞懂这题什么意思。.大家给解答下吧~`

3.A hiker walking at a constant rate of 4 miles per hour is passed by a cyclist traveling in the same direction along the same path at a constant rate of 20 miles per hour. The cyclist stops to wait for the hiker 5 minutes after passing her, while the hiker continues to walk at her constant rate. How many minutes must the cyclist wait until the hiker catches up?

(A) 6+2/3

(B) 15

(D) 25

(E) 26+2/3

答案是C.

我奇怪的是骑车的人超过走路的人之后就停下来等走路的人...超过不是一瞬间的事嘛..骑车的人一停.他不就落后于走路的人了么?

最后怎么求走路人追赶骑车人的时间啊?

他们之间的距离怎么算捏?

作者: 冰岛哲学C 时间: 2007-12-9 21:46

顶吖~~~

XDJM们...看一眼呐....呃~~~

作者: 冰岛哲学C 时间: 2007-12-10 18:00

我很厚脸皮的再顶下好了.因为过8天就考了..但是..数学还是很迷茫~~怀疑是解题思路的问题~~

作者: allenchi 时间: 2007-12-11 00:50

第一题,我也见过,是不是N未知的原因,另一个条件是不是N=什么数值所以选C?

第二题,中数是330000,就说明ANN和CAL有一个是330000,ANN还要比CAL多.文中说的是CAL的一部分帐错当成了ANN的,但总数和其他人并无影响

第三题,只能把5 minutes after passing her当成时状,修饰stops

(20-4)*(5/60)/(4/60)

作者: 冰岛哲学C 时间: 2007-12-11 12:59

第一题给的另一个条件是充分的. 即1/3N的人平均身高为BLABLA..剩下2/3N的人平均身高为BLABLA...

第2题和第3题楼上解释的真好.已经看懂啦~~HOHO~`

原来我还是审题的问题..总是看不懂题目..唉...

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