| A farmer has 100 gallons of 70% pure disinfectant. He wishes to mix it with disinfectant which is 90% pure in order to obtain 75% pure disinfectant. How much of the 90% pure must he use? |
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Find FIRST
Let Y = Number of Gallons of 90 percent solution 0.7*100 + 0.9*Y = 0.75(Y + 100) (0.9-0.75)Y = 100(0.75-0.7) 0.15Y = 5 Y = 33.33 Y = 33.33 Gallons |