You would have to give 0.25 mL of the drug every 15 s.
This is a problem in unit conversion.
You have to convert seconds → minutes → milligrams of drug → millilitres of drug
15 s ×
1 min
60 s
×
37.5 mg
15 min
×
1 mL
2.5 mg
= 0.25 mL
You would have to give 0.25 mL of the drug every 15 s.