Question

他们得知同一晚有一场大型音乐会，出席人数会减少 $25\%$ 。他们应该为这个较小的聚会做多少份饼干食谱？

They learn that a big concert is scheduled for the same night and attendance will be down $25\%.$ How many recipes of cookies should they make for their smaller party?

$6$

$8$

$9$

$10$

$11$

答案：E

知识点：百分数取整函数

难度评级：1310

解答：

现在聚会上只有人。这意味着需要份食谱。 $108 \cdot \left(1 - \dfrac{1}{4}\right) = 108 \cdot \dfrac{3}{4} = 81$ $\left\lceil \dfrac{81 \cdot 2}{15} \right\rceil = \left\lceil \dfrac{162}{15} \right\rceil = 11$

所以正确答案是 E。

There will now only be $108 \cdot \left(1 - \dfrac{1}{4}\right) = 108 \cdot \dfrac{3}{4} = 81$ people at the party. This means we need $\left\lceil \dfrac{81 \cdot 2}{15} \right\rceil = \left\lceil \dfrac{162}{15} \right\rceil = 11$ recipes.

Thus, E is the correct answer.

1999 AMC 8 第 18 题

答案：E

难度评级：1310

解答：

其他年份的第 18 题