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饮丹

Drinking Dan

专题
Brainteaser / 脑筋急转弯
难度
L1

题目详情

丹有 2 个眼镜。第一个杯子 34\frac{3}{4} 装满了水,而第二个杯子是空的。然后他把第一个杯子里的水全部倒到第二个杯子里,第二个杯子就变成了装满水的23\frac{2}{3}。第一个玻璃的体积除以第二个玻璃的体积分数是多少?

Dan has 2 glasses. The first glass was 34\frac{3}{4} full of water while the second was empty. He then poured all the water from the first glass to the second, which then became 23\frac{2}{3} full of water. What is the fraction of the volume of the first glass divided by the second?

解析

我们将第一个玻璃的体积表示为 x\textit{x},将第二个玻璃的体积表示为 y\textit{y}。我们现在可以将这两个卷等同为 34x=23y\frac{3}{4}x = \frac{2}{3}y。这是因为第一个玻璃杯 (x) 已满 34\frac{3}{4},将其全部内容物倒入第二个玻璃杯 (y) 后,它已满 23\frac{2}{3}。所以第一个杯子的 34\frac{3}{4} 等于第二个杯子的 23\frac{2}{3}。现在要求我们求解第一个玻璃的体积除以第二个玻璃的体积的分数或比率。我们被要求求解 xy\frac{x}{y} 的比率。我们可以对原始等式进行代数运算以获得 xy=2334\frac{x}{y} = \frac{\frac{2}{3}}{\frac{3}{4}}。或者,xy=89\frac{x}{y} = \frac{8}{9}。因此体积比为 89\frac{8}{9}(第二个比第一个大 18\frac{1}{8}12.512.5%)。


Original Explanation

Let’s denote the volume of the first glass as x\textit{x}, and the volume of the second glass as y\textit{y}. We can now equate the two volumes as 34x=23y\frac{3}{4}x = \frac{2}{3}y. This is because the first glass (x) was 34\frac{3}{4} full, and after pouring it’s entire contents into the second glass (y), it became 23\frac{2}{3} full. So 34\frac{3}{4} of the first cup is equal to 23\frac{2}{3} of the second glass. We are now asked to solve for the fraction or ratio of the volume of the first glass divided by the volume of the second. We’re asked to solve for the ratio xy\frac{x}{y}. We can perform algebraic manipulations on our original equality to attain xy=2334\frac{x}{y} = \frac{\frac{2}{3}}{\frac{3}{4}}. Or, xy=89\frac{x}{y} = \frac{8}{9}. So the ratio of volumes is 89\frac{8}{9} (the second one is larger than the first by 18\frac{1}{8} or 12.512.5%).