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标题: 求助数学题目 [打印本页]

作者: 水享 时间: 2010-10-24 22:31
标题: 求助数学题目
请XDJM们帮我解释几道数学题，本人数学很差，所以麻烦各位解释稍微多点，多谢了！
1.. a certain culture of bacteria quadruples every hour. if a container with these bacteria was half full at 10:00a.m., at what time was it one-eighth full? A. 9:00am B. 7:00am C. 6:00am D. 4:00am E. 2:00am 答案是A

2.a certain basketball team that has played 2/3 of its games has record of 17 wins and 3 losses. what is the greatest number of the remaining games that the team can lose and still win at least 3/4 of all of its games?A.7 B.6 C.5 D.4 E.3 答案是D

3. there were 36000 hardback copies of a certain novel sold before the paperback version was issued. from the time the first paperback copy was sold until the last copy of the novel was sold. 9 times as many paperback copies as hardback copies were sold. if a total of 441000 copies of the novel were sold in all, how many paperback copies were sold?
A. 45000 B. 360000 C.364500 D.392000 E396900 答案是C

作者: cdcharlie 时间: 2010-10-24 22:39
1.quadruples是四倍的意思。10点是1/2,1/8是1/2的四分之一，就是一小时前。
2.17+3=20 20除以2/3是总数，就是一共要打30场。要赢3/4场，就是说一共要赢30* （3/4）=22.5 现在赢了17了，还差6场到超过22.5。然后问还能输几场，就是10-6=4
3.在软皮的版本出来前，硬皮的卖了36000。从第一个软皮的版本卖出到卖完，卖出软皮的数量是硬皮的9倍。一共卖了441000。用441000-36000=405000 这个数是软皮版本推出后，软皮+硬皮一共卖的出的数量。根据从第一个软皮的版本卖出到卖完，卖出软皮的数量是硬皮的9倍，405000*（9/10）=364500

作者: 水享 时间: 2010-10-25 13:26
那个第三题最后一步405000*（9/10）那个10是怎么得来的？

作者: 水享 时间: 2010-10-25 13:28

1.quadruples是四倍的意思。10点是1/2,1/8是1/2的四分之一，就是一小时前。
2.17+3=20 20除以2/3是总数，就是一共要打30场。要赢3/4场，就是说一共要赢30* （3/4）=22.5 现在赢了17了，还差6场到超过22.5。然后问还能输几场，就是10-6=4
3.在软皮的版本出来前，硬皮的卖了36000。从第一个软皮的版本卖出到卖完，卖出软皮的数量是硬皮的9倍。一共卖了441000。用441000-36000=405000 这个数是软皮版本推出后，软皮+硬皮一共卖的出的数量。根据从第一个软皮的版本卖出到卖完，卖出软皮的数量是硬皮的9倍，405000*（9/10）=364500

-- by 会员 cdcharlie (2010/10/24 22:39:46)

第三题最后一步，405000*（9/10）中10是怎么得来的啊？

作者: amy0208 时间: 2010-10-25 13:52

-- by 会员 cdcharlie (2010/10/24 22:39:46)

第三题最后一步，405000*（9/10）中10是怎么得来的啊？

-- by 会员水享 (2010/10/25 13:28:47)

405000包括软皮和硬皮的总和。其中软皮是硬皮的9倍，所以软皮占了9/10

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