molarity=number of moles/volume
First we find the number of moles of NaOH we have the molarity and the volume we transform mililiters in liters 100ml=0.1l
12=n/0.1 n=1.2 moles of NaOH
now we find the volume of the second solution
4.75=1.2/V
V=1.2/4.75=0.252l
0.252-0.1=0.152liters=152ml of pure water used to dilute