2005 AMC 10B 第 5 题

Question

Brianna 用周末打工赚来的一部分钱购买若干张价格相同的 CD。她用自己钱的五分之一买了全部 CD 的三分之一。她买完所有 CD 后，还剩自己钱的几分之几？

Brianna is using part of the money she earned on her weekend job to buy several equally-priced CDs. She used one fifth of her money to buy one third of the CDs. What fraction of her money will she have left after she buys all the CDs?

\dfrac15

\dfrac13

\dfrac25

\dfrac23

\dfrac45

答案：C

知识点：分数比与比例钱币

难度评级：960

小提示：

买完全部 CD 的花费是买三分之一 CD 的三倍。

Buying all the CDs costs three times as much as buying one third of them

大提示：

全部 CD 花掉她钱的

3\cdot\dfrac15

。

All the CDs cost

3\cdot\dfrac15

of her money

解答：

买完所有 CD 的花费是买三分之一 CD 的三倍，即她的钱的

3 \cdot \dfrac15 = \dfrac35

。

剩下的部分为

1 - \dfrac35 = \dfrac25

。

所以正确答案是 C。

Buying all the CDs costs three times as much as buying one third of them, namely

3 \cdot \dfrac15 = \dfrac35

of her money.

The fraction left over is

1 - \dfrac35 = \dfrac25.

Thus, C is the correct answer.

2005 AMC 10B 第 5 题

答案：C

难度评级：960

小提示：

大提示：

解答：

其他年份的第 5 题