Using the formula for the rate of flow (micro drops per minute) as (Volume in ml * 15) / Time in minutes, the rate of flow for infusing 40 ml of IV fluid over 60 minutes is 10 micro drops per minute.
The volume = 40 ml
The time = 60 minutes
Rate of flow = (40 * 15) / 60
Rate of flow = 600 / 60
Rate of flow = 10 micro drops per minute
Thus, we can conclude that the rate of flow for infusing 40 ml of IV fluid over 60 minutes is 10 micro drops per minute.