Question

How is a `5*%v/v` solution of methanol in water prepared?

Answer 1

Take `45*mL` of water and add `5*mL` of methanol. The volumes should be additive and you are left with `5%` methanol, `v/v`.

Explanation:

Of course that method works to a first approximation, and here the dilution is `"volume of solute"/"volume of solution"`. If you want `"mass of solute"/"mass of solution"` you add appropriate masses. The actual concentrations will not be that different.