AMC12 2005 A
AMC12 2005 A · Q1
AMC12 2005 A · Q1. It mainly tests Percent, Arithmetic misc.
Two is $10 \%$ of $x$ and $20 \%$ of $y$. What is $x - y$?
2 是 $x$ 的 $10 \%$，也是 $y$ 的 $20 \%$。$x - y$ 是多少？
(A)
1
1
(B)
2
2
(C)
5
5
(D)
10
10
(E)
20
20
Answer
Correct choice: (D)
正确答案：（D）
Solution
$2 = \frac {1}{10}x \Longrightarrow x = 20,\quad 2 = \frac{1}{5}y \Longrightarrow y = 10,\quad x-y = 20 - 10=10 \mathrm{(D)}$.
$2 = \frac {1}{10}x \Longrightarrow x = 20,\quad 2 = \frac{1}{5}y \Longrightarrow y = 10,\quad x-y = 20 - 10=10 \mathrm{(D)}$.
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