Question
A 60-litre mixture of acid and water contains 33(1/2%)Â
acid. How much water (in litres) must be added to get a mixture having 25% acid?Solution
In 60 liters solution 34 liter acid and 66 liter water In 60 liters solution, water is (66/100) × 60 = 6.6 x 6 = 39.6 or ~ 40 liter On adding x liters of water [(40 + x)/(60 + x)] x 100 = 75 On dividing 100 and 75 we get 4 and 3 value then [(40 + x)/(60 + x)] x 4 = 3 (160 + 4x)/(60 + x ) = 3 160 + 4x = (60 + x) x 3 160 + 4x = 180 + 3x 4x - 3x = 180 - 160 x = 20 Liter
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