Question

A doctor has ordered that a patient be given 15g of glucose, which is available in a concentration of 75.00g glucose/1000.0 mL of solution.What volume of solution should be given to the patient?

Answer 1

Given the concentration (C) in mass per volume, the volume (V) of the solution is obtained by dividing the mass (m) by this concentration (C). So, from the given,
                         V = C / m   = (15 g) / (75 g / 1000 mL)
The numerical value of V is equal to 200 mL. 

Answer 2

I would start by converting g/mL to g/L
75.00g/1000.0mL = 75.00g/L
Stoichiometrically, flip 75 onto the bottom so that grams cancel out and we are left with the number of L required. 
(L/75.00g)(15g) -> this is essentially dividing 15g by 75g, which cancels the unit g, leaving us with 0.2L. If the question requires an answer in mL, just multiple the number of L by 1000. 
The patient requires 200mL of glucose solution to receive his 15g of glucose.