SOLUTION: Pure acid is to be added to a 10% acid solution to obtain 90L on 20% solution. What amounts of each should be used? How many liters of 100% pur acid should be used? H0w many li

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Question 817404: Pure acid is to be added to a 10% acid solution to obtain 90L on 20% solution. What amounts of each should be used?
How many liters of 100% pur acid should be used?
H0w many liters of the 10% soultion should be in the mixture?

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Let u = liters of the 10% acid.
Let v = liters of the 100% acid.
You did not say if the percents are as v/v or as w/v, so this solution guidance assumes v/v.

Amount of acid =10u%2B100v, and represents 100 times the actual amount of acid, because the percents are used;
Amount of resulting solution is 90 liters.
You wanted 20% acid as a result:

%2810v%2B100v%29%2F90=20 and u%2Bv=90
Solve the system.