Question

Cagney 每 $20$ 秒给一个纸杯蛋糕涂糖霜，Lacey 每 $30$ 秒给一个纸杯蛋糕涂糖霜。两人一起工作， $5$ 分钟内可以给多少个纸杯蛋糕涂糖霜？

Cagney can frost a cupcake every $20$ seconds and Lacey can frost a cupcake every $30$ seconds. Working together, how many cupcakes can they frost in $5$ minutes?

$10$

$15$

$20$

$25$

$30$

答案：D

知识点：速率单位换算

难度评级：560

解答：

Cagney 每分钟完成 $60 \div 20 = 3$ 个，Lacey 每分钟完成 $60 \div 30 = 2$ 个。

$5$ 分钟内，他们能完成 $5(2 + 3) = 5 \cdot 5 = 25.$

所以正确答案是 D。

Cagney can make $60 \div 20 = 3$ cupcakes per minute, and Lacey can make $60 \div 30 = 2.$

In $5$ minutes, they can make $5(2 + 3) = 5 \cdot 5 = 25.$

Thus, D is the correct answer.

2012 AMC 10A 第 1 题

答案：D

难度评级：560

解答：

其他年份的第 1 题