How many liters each of 15% acid and 33% acid should be mixed to get 120 L of 21% acid?

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Answer 1 · 2018-07-24T14:12:32

The volume of #15%# is #=80L# and the volume of #33%# is #=40L#

Perform a material balance

The total volume is #=120L#

Let the volume of #15%# acid be #=vL#

Then,

The volume of #33%# acid is #=(120-v)L#

The final percentage is #=21%# acid

Therefore,

#v*15/100+(120-v)*33/100=120*21/100#

#15v+120*33-33v=120*21#

#18v=120(33-21)=1440#

#v=1440/18=80L#