Question

How much of 30% HCI and 45% HCI would be needed to mix and produce 50 liters of 35% HCI

Answer 1

• 33 1/3 liters of 30%
• 16 2/3 liters of 45%

Explanation:

Let x represent the liters of 45% solution needed. Then the amount of HCl in the mix is ...

0.45x +0.30(50 -x) = 0.35(50)

0.15x = 0.05(50) . . . . . simplify, subtract 0.30(50)

x = (0.05/0.15)(50) = 50/3 = 16 2/3 . . . liters of 45% HCl

33 1/3 liters of 30% and 16 2/3 liters of 45% HCl are needed.

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Comment on the solution

You may notice that the general solution to a mixture problem of this sort is that the fraction of the mix that is the highest contributor is ...

(mix % - low %) / (high % - low %) = (.35 -.30) / (.45 -.30) = .05/.15 = 1/3