How much codeine is needed to prepare 120 ml of a cough syrup with a codeine concentration of 15 mg/ml?

15 mg/ml * 120ml = 1800 mg

To determine how much codeine is needed to prepare a 120 ml cough syrup with a codeine concentration of 15 mg/ml, you can use the formula:

Amount of codeine = Volume of syrup × Concentration of codeine

In this case, the volume of syrup is given as 120 ml, and the concentration of codeine is 15 mg/ml. Plugging these values into the formula, we get:

Amount of codeine = 120 ml × 15 mg/ml

Simplifying this equation, we find:

Amount of codeine = 1800 mg

Therefore, to prepare a 120 ml cough syrup with a codeine concentration of 15 mg/ml, you would need 1800 mg of codeine.