I have the following substrates:

+Mixed acid (MA) which consists of:
- 35% nitric acid
- 65% sulfuric acid
+Spent acid (SPA) which consists of:
- 1% nitric acid
- 80% sulfuric acid
- 19% water

My goal is to mix the substrates so I will get a mixture of 15% nitric acid, 70% sulfuric acid and 15% water. I can add water but I should not add pure substances if possible.

Can you help, /sci/? How should I take this problem? I used the method given in literature (Urbanski), but the results are shit.