Question

假设 $10$ 根香蕉的 $\tfrac{2}{3}$ 与 $8$ 个橙子价值相同。那么 $5$ 根香蕉的 $\tfrac{1}{2}$ 与多少个橙子价值相同？

Suppose that $\tfrac{2}{3}$ of $10$ bananas are worth as much as $8$ oranges. How many oranges are worth as much as $\tfrac{1}{2}$ of $5$ bananas?

$2$

$\dfrac{5}{2}$

$3$

$\dfrac{7}{2}$

$4$

答案：C

知识点：比与比例

难度评级：1100

解答：

因为 $10$ 根香蕉的 $\tfrac{2}{3}$ 是 $\tfrac{20}{3}$ 根，价值 $8$ 个橙子，所以一根香蕉价值个橙子。 $8 \div \dfrac{20}{3} = \dfrac{24}{20} = \dfrac{6}{5}$

于是 $5$ 根香蕉的 $\tfrac{1}{2}$ 是 $\tfrac{5}{2}$ 根香蕉，价值个橙子。 $\dfrac{5}{2} \cdot \dfrac{6}{5} = 3$

所以正确答案是 C。

Since $\tfrac{2}{3}$ of $10$ bananas is $\tfrac{20}{3}$ bananas, worth $8$ oranges, one banana is worth $8 \div \dfrac{20}{3} = \dfrac{24}{20} = \dfrac{6}{5}$ oranges.

Then $\tfrac{1}{2}$ of $5$ bananas is $\tfrac{5}{2}$ bananas, worth $\dfrac{5}{2} \cdot \dfrac{6}{5} = 3$ oranges.

Thus, C is the correct answer.

2008 AMC 12A 第 3 题

答案：C

难度评级：1100

解答：

其他年份的第 3 题