AMC 8 1989 Problem 13

AMC8 1989 年第 13 题

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题干整理中

  1. A.0.90.7×53\displaystyle \frac{0.9}{0.7×53}
  2. B.0.90.7×0.53\displaystyle \frac{0.9}{0.7×0.53}
  3. C.0.90.7×5.3\displaystyle \frac{0.9}{0.7×5.3}
  4. D.0.97×0.53\displaystyle \frac{0.9}{7×0.53}
  5. E.0.090.07×0.53\displaystyle \frac{0.09}{0.07×0.53}

正确答案 · Correct Answer

A

解析 · Solution

Solution 1

Notice that 97×53=.1×9.1×7×53=.9.7×53\displaystyle \frac{9}{7×53} = \frac{.1×9}{.1×7 \times 53} = \frac{.9}{.7×53}. Choices (B) and (E) are 100 times the original expression while choices (C) and (D) are 10 times the original expression.

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