Question

一盒牛奶含 $2\%$ 脂肪，这比一盒全脂牛奶所含脂肪少 $40\%$ 。全脂牛奶的脂肪百分比是多少？

A carton contains milk that is $2\%$ fat, an amount that is $40\%$ less fat than the amount contained in a carton of whole milk. What is the percentage of fat in whole milk?

$\dfrac{12}{5}$

$3$

$\dfrac{10}{3}$

$38$

$42$

答案：C

知识点：百分数一次方程

难度评级：960

解答：

设全脂牛奶含脂肪 $x\%$ 。因为 $2$ 比 $x$ 少 $40\%$ ，所以 $0.6x = 2,$ 从而 $x = \dfrac{2}{0.6} = \dfrac{10}{3}.$

所以正确答案是 C。

Let whole milk be $x\%$ fat. Since $2$ is $40\%$ less than $x,$ we have $0.6x = 2,$ so $x = \dfrac{2}{0.6} = \dfrac{10}{3}.$

Thus, the correct answer is C.

2009 AMC 10A 第 7 题

答案：C

难度评级：960

解答：

其他年份的第 7 题