mary works at the hospital as a nurse,she inserted an I-v to a patient at 8:00am.the I-v bag has a drip rate of 4ml per minute and the i-v bag is 1000ml.
the IV rate means that the time for 1000ml at a rate of 4ml/minute is found with 1000ml=4ml/minute*Xminutes. Divide by 4 and get 250minutes=X. If you convert this to time as kept standardly you get 250/60=4+10/60, or four hours and 10 minutes. Add this to the current time to attain a time of 12:10pm or 10 minutes past noon is when Mary would have to replace the i-V drip.