Titration calculation issue (1 Viewer)

[MilkDrinker]

Hi guys...
Could you help me out in trying to understand a question from conquering chemistry, chapter 5, question 20?

25 mL of sulfuric acid from a car battery was accurately diluted to 500mL. 25mL of the diluted solution was titrated with 0.206 mol/L sodium hydroxide. It required 38.8mL. Calculate the molarity of the original battery acid and its concentration in grams per litre.

I think I know how to get the concentration of the dilute solution (I get around 0.159856... mol/L). I do not understand how to find the initial concentration of the sulfuric acid.

Your help would be much appreciated...
Thanks

 

[golgo13]

C1v1=c2v2