Percent

Two liters of a 30%  acid solution are mixed with three liters of a 70% acid solution. What percent of the mixture is acid?    

2 liters @ 30% acid  =  0.6 liter acid & 1.4 liter water    

3 liters @ 70% acid  =  2.1 liter acid & 0.9 liter water    

adding them up            2.7 liter acid & 2.3 liter water    

This is a total 5.0 liter solution, 2.7 liters of which is acid    

2.7 / 5.0  =  0.54  ——>>  The new solution is 54% acid    

Confirm plausibility:  2.7 is a little more than half of 5.0    

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