AMC 8 2013 Problem 2
AMC8 2013 年第 2 题
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A sign at the fish market says, "50 % off, today only: half-pound packages for just $3 per package." What is the regular price for a full pound of fish, in dollars?
鱼市上的一则标语写着：“降价 50％，仅限今天：半磅重的一包鱼仅需 3 美元。”那么一磅重的鱼原价是多少美元？
- A.6
- B.9
- C.10
- D.12
- E.15
正确答案 · Correct Answer
D
解析 · Solution
Solution 1
50% off the price of half a pound of fish is $3, so 100%, the regular price, of a half pound of fish is $6. If half a pound of fish costs $6, then a whole pound of fish is 12 dollars.
Suppose a full pound at normal price costs dollars. Then, with the 50% off deal, the full pound would cost x/2 dollars. A half pound of this would cost x/4 dollars (including the 50% off). 50% off half a pound is 3, so we form the equation .
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