Question 1040249
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Twenty grams of solution P is 10%  alcohol and 30 grams of solution is 20%  alcohol by mass these two solutions are mixed together,  
what is the percent of alcohol in the mixture?
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The amount of the pure alcohol in 20 grams of 10% solution is 0.1*20 = 2 grams.

The amount of the pure alcohol in 30 grams of 20% solution is 0.2*30 = 6 grams.

In total, the amount of the pure alcohol in the mixture is 2 + 6 = 8 grams.

The mass of the mixture is 20 grams + 30 grams = 50 grams.

The concentration of the alcohol in the mixture is {{{8/50}}} = {{{16/100}}} = 16%.

<U>Answer</U>.  The concentration of the alcohol in the mixture is 16%.
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