Explanation:
The given data is as follows.
Concentration of phenytoin suspension stock = 30 mg/5mL
Concentration of phenytoin required = 20 mg/5 mL
Volume of phenytoin required = 150 mL
Volume of phenytoin suspension stock required for dilution will be calculated as follows.
[tex]20 \times \frac{150}{30}[/tex]
= 100 mL
Thus, we can conclude that the volume of phenytoin is 100 mL .