AMC 8 2001 Problem 15
AMC8 2001 年第 15 题
工程问题★★★☆☆
Homer began peeling a pile of 44 potatoes at the rate of 3 potatoes per minute. Four minutes later Christen joined him and peeled at the rate of 5 potatoes per minute. When they finished, how many potatoes had Christen peeled?
Homer 开始以每分钟 3 个土豆的速度开始剥一堆土豆，这堆土豆总共有 44 个。四分钟后， Christen 加入他的行列，以每分钟 5 个土豆的速度剥皮。当他们完成时，Christen 剥了多少土豆？
- A.20
- B.24
- C.32
- D.33
- E.40
正确答案 · Correct Answer
A
解析 · Solution
Solution 1
After the 4 minutes of Homer peeling alone, he had peeled 4×3=12 potatoes. This means that there are 44-12=32 potatoes left. Once Christen joins him, the two are peeling potatoes at a rate of 3+5=8 potatoes per minute. So, they finish peeling after another minutes. In these 4 minutes, Christen peeled 20 potatoes.
After the 4 minutes of Homer peeling alone, he had peeled 4×3=12 potatoes. This means that there are 44-12=32 potatoes left. Once Christen joins him, the two are peeling potatoes at a rate of 3+5=8 potatoes per minute. Because Christen's rate is 5, she peels 5/8 of 32, or 20 potatoes. -N.
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