AMC 8 1985 Problem 6
AMC8 1985 年第 6 题
比与比例★★☆☆☆
A ream of paper containing 500 sheets is 5 cm thick. Approximately how many sheets of this type of paper would there be in a stack 7.5 cm high?
一令纸含有 500 张，厚度为 5 厘米。同类型的纸叠成 7.5 厘米高的一摞，大约有多少张？
- A.250
- B.550
- C.667
- D.750
- E.1250
正确答案 · Correct Answer
D
解析 · Solution
Solution 1
Each sheet is thick, so a stack contains sheets.
Since each sheet has the same thickness, the number of sheets in a stack is directly proportional to the thickness of a stack.
Let be the number of sheets in a stack. Then , so 5x=3750 and thus x = 750.
Using dimensional analysis with the conversion factor yields .
Each centimeter of a stack contains sheets of paper, so a stack must contain sheets of paper.
Since a stack is 1.5 times as thick as a stack, a stack contains sheets of paper.
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