[maya]

I have an analytical chem problem that gives me the volume (20 mL) and concentration(0.1 M) of a strong acid and the volume (25 mL) of a weak base.  The problem asks for the concentration of the base.  I know how to solve these  problems when they involve strong acids and strong bases, but I'm not sure I can do it the same if they are not both strong.  Can anyone tell me how to solve this type of problem?

Thanks!