



 
Hi Leeanne. The concentration times the volume of a mixture tells you how much of the active ingredient is in there. So the chemist starts with 200x(5%) = 10 liters of the acid itself. The question is this: 10 liters is 4% of what number? 10 liters = 4% of x. 10 = 0.04(x) 10 / 0.04 = 0.04x / 0.04 So the total volume of the 4% solution the chemist makes is 250 liters. That's 50 liters more than she started with. So she added 50 liters of water to the original solution. Cheers,  


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