[fardeen_gen]

What volume of 1.0 M HCl should be mixed with how much 0.25 M HCl in order to prepare 1.0 L of 0.5 M HCl?
A)667 mL & 333 mL
B)667 mL & 750 mL
C)500 mL & 750 mL
D)250 mL & 750 mL

My working: 1 L of 0.5 M HCl has normality 0.5 N. Using the values given in the options, none of the resulting solutions seem to have the same normality.

[Arkcon]

There is, in fact, no chemistry here, just a weighted average.  You could replace the units with currency, if you felt like it, and it would be the same problem.  FWIW, there is an answer.  I actually plugged this into a spreadsheet, because I am notoriously bad at math.  When you solve it yourself, I hope you give yourself the same "Augh.  Dumkopf!" *Head slap* That I just gave myself, because the answer is soooo...obvious

[AWK]

The answer is given as volume of 0,25 M & volume 1 M