I drank 40 grams of solution for the second time, leaving 60 grams of solution. At this time, there is 60×48%=28.8 grams of solute in the bottle, which is filled with clear water. At this time, the solution is 100g and the solute is 28.8g, so the concentration is 28.8/ 100=28.8%.
I drank 40 grams of solution for the third time, leaving 60 grams of solution. At this time, there is still 60× 28.8% =17.28g solute in the bottle, which is filled with clear water. At this time, the solution is100g and the solute is 17.28g, so the concentration is 17.28/65438.