Problema Solution
you have 4 litres of 30% alcohol solution. How many litres of pure water needs to be added to make a 5% alcohol solution?
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Solution
Amount of
solution
% alcohol
Amount of
alcohol
pure water
x
0
(0)(x)
30% solution
4
0.3
(0.3)(4)
5% mixture
4 + x
0.05
(0.05)(4 + x)
Equation setup: (0)(x) + (0.3)(4) = (0.05)(4 + x)
Answer: x = 20 liters