Question

Pure acid is to be added 5% acid solution to obtain 95 liter of 69% solution. What amounts of each should be used? How many liters of the 5% solution should be in the mixture,

Answer 1

ratio of
pure acid : 5%
= (69-5) : (100-69)
= 64 : 31
Out of 95L of mixture,
Pure acid=95(64/(64+31))=95*(64/95)=64 L
5% acid = 95(31/(64+31))=95*(31/95)=31 L
Check: total=64+31=95L ok.