AMC12 2013 B

AMC12 2013 B · Q2

AMC12 2013 B · Q2. It mainly tests Rates (speed), Area & perimeter.

Mr. Green measures his rectangular garden by walking two of the sides and finds that it is 15 steps by 20 steps. Each of Mr. Green’s steps is 2 feet long. Mr. Green expects a half a pound of potatoes per square foot from his garden. How many pounds of potatoes does Mr. Green expect from his garden?

格林先生通过步行测量他的矩形花园的两条边，发现是15步乘20步。格林先生每步长2英尺。他期望花园每平方英尺产半磅土豆。格林先生期望从他的花园收获多少磅土豆？

(A) 600 600

(B) 800 800

(D) 1200 1200

(E) 1400 1400

Answer

Correct choice: (A)

正确答案：（A）

Solution

The garden is $2 \cdot 15 = 30$ feet by $2 \cdot 20 = 40$ feet. Hence Mr. Green expects $\frac{1}{2} \cdot 30 \cdot 40 = 600$ pounds of potatoes.

花园是$2 \cdot 15 = 30$英尺乘$2 \cdot 20 = 40$英尺。因此格林先生期望$\frac{1}{2} \cdot 30 \cdot 40 = 600$磅土豆。

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