maths
2011-08-27 7:05 am
3 kg of a solution contains 40% of alcohol by weight . How much alochol should be added to obtain a solution containg 50% of alcohol by weight in kg ?
回答 (2)
2011-08-27 7:20 am
✔ 最佳答案
Originally, there are 3 * 40% = 1.2 kg alcohol in the solutionLet the alcohol should be added is x kg
(1.2 + x)/(3 + x) = 0.5
1.2 + x = 1.5 + 0.5x
0.5x = 0.3
x = 5/3 kg
2011-08-27 7:12 am
Amount needed to add
= 3/40% * 50% - 3
= 5/4 * 3 - 3
= 15/4 - 3
= 3/4 kg
= 3/40% * 50% - 3
= 5/4 * 3 - 3
= 15/4 - 3
= 3/4 kg
參考: Hope the solution can help you^^”
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