120 ml of sugar solution has a density of 1.22g/cm3. when an additional unknown amount of sugar was added to the solution, the volume of the solution was raised by 15ml and the density becomes 1.38g/cm3. how much sugar was added to the solution

You added 40 g sugar to the solution.

Step 1. Calculate the mass of the first solution.

Mass1 = 120 mL * (1.22 g/1 mL) = 146.4 g

Step 2. Calculate the mass of the second solution.

Volume 2 = 120 mL + 15 mL = 135 mL

Mass 2 = 135 mL * (1.38 g/1 mL) = 186.3 g

Step 3. Calculate the mass of the sugar.

Mass of sugar = mass2 - mass1 = 186.3 g - 146.4 g = 40 g