Question

Paul 欠 Paula $35$ 美分，并且口袋里有 $5$ 美分、 $10$ 美分和 $25$ 美分硬币可用来付钱。他可以用来支付的硬币数最大值与最小值之差是多少？

Paul owes Paula $35$ cents and has a pocket full of $5$ -cent coins, $10$ -cent coins, and $25$ -cent coins that he can use to pay her. What is the difference between the largest and the smallest number of coins he can use to pay her?

$1$

$2$

$3$

$4$

$5$

答案：E

知识点：钱币最优化

难度评级：450

解答：

要使用最多硬币，Paul 可以全用 $5$ 美分硬币，得到 $35/5=7$ 枚。

要使用最少硬币，他可以用一枚 $25$ 美分和一枚 $10$ 美分硬币，共 $2$ 枚。差为 $7-2=5$ 。

所以正确答案是 E。

To use the largest number of coins, Paul would use only $5$ -cent coins, which gives $35/5=7$ coins.

To use the smallest number of coins, Paul would use a $25$ -cent coin and a $10$ -cent coin, for a total of $2$ coins. The difference is $7-2=5$ .

Thus, E is the correct answer.

2014 AMC 8 第 2 题

答案：E

难度评级：450

解答：

其他年份的第 2 题