Question by Summer Clouds - Discuss with MathYouLike

Summer Clouds moderators

21/09/2017 at 09:16

1000 kg of a chemical is stored in a container. The chemical is made up of 99 % water and 1 % oil. Some water is evaporated from the chemical until the water content is reduced to 96 %. How much does the chemical weigh now?

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Phan Thanh Tinh Coordinator 21/09/2017 at 09:59

The weigh of the water in the chemical is : 1000 x 99% = 990 (kg)

Let x kg be the weigh of the evaporated water, then :

\(\dfrac{990-x}{1000-x}=96\%\Leftrightarrow990-x=96\%\left(1000-x\right)\)

\(\Leftrightarrow990-x=960-\dfrac{24}{25}x\Leftrightarrow990-960=-\dfrac{24}{25}x+x\)

\(\Leftrightarrow\dfrac{1}{25}x=30\Leftrightarrow x=750\Leftrightarrow1000-x=250\)

So, the answer is 250 kg
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Phan Minh Anh 21/09/2017 at 12:23

The answer is 250 kg. 100%

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