SOLUTION: A crop dusting service needs to prepare a 0.4% pesticide solution. It has an airplane with a 200-gal tank that contains 75 gal of a 1% solution. How much water should be added to t

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Question 1041597: A crop dusting service needs to prepare a 0.4% pesticide solution. It has an airplane with a 200-gal tank that contains 75 gal of a 1% solution. How much water should be added to the tank to decrease the concentration to the desired 0.4% level?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Just add water to the tank? What is this expected final volume?

v, volume of water to add to the 75 gallons of 1% solution;

75%2A0.01%2F%2875%2Bv%29=0.004 as decimal fractions;

75%2A1%2F%28v%2B75%29=0.4 as percents

75=0.4%28v%2B75%29

750=4v%2B4%2A75

4v=750-4%2A75

4v=450

highlight%28v=450%2F4=highlight_green%28112.5%29%29
Now, is this enough or too much for the 200 gallon tank?
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112.5%2B75=187.5%3C=200