AMC10 2005 A

AMC10 2005 A · Q1

AMC10 2005 A · Q1. It mainly tests Percent, Interest / growth (simple).

While eating out, Mike and Joe each tipped their server $2. Mike tipped 10% of his bill and Joe tipped 20% of his bill. What was the difference, in dollars, between their bills?

外出就餐时，Mike 和 Joe 各给了服务员 2 美元小费。Mike 的小费是他账单的 10%，Joe 的小费是他账单的 20%。他们的账单差额是多少美元？

(A) 2 2

(B) 4 4

(D) 10 10

(E) 20 20

Answer

Correct choice: (D)

正确答案：（D）

Solution

(D) Since Mike tipped \$2, which was $10\% = \frac{1}{10}$ of his bill, his bill must have been $2 \cdot 10 = 20$ dollars. Similarly, Joe tipped \$2, which was $20\% = \frac{1}{5}$ of his bill, so his bill must have been $2 \cdot 5 = 10$ dollars. The difference between their bills is therefore \$10.

（D）由于 Mike 给了 \$2 小费，这相当于他账单的 $10\% = \frac{1}{10}$，所以他的账单应为 $2 \cdot 10 = 20$ 美元。同样，Joe 给了 \$2 小费，这相当于他账单的 $20\% = \frac{1}{5}$，因此他的账单应为 $2 \cdot 5 = 10$ 美元。所以他们账单的差额为 \$10。

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