To determine the many mls will you give to “Lucy”:
Using a weight measurement by volume conversion

Mass = 16kg
dose = 22mg/kg
density = 100mg/ml
How many mgs of cefazolin will you give to “Lucy

Hence the mass (mgs) of cefazolin given to lucy = 352 mgs

Hence the volume (mls) given to lucy = 3.52 ml