Answer: 3.2
Step-by-step explanation: First you are going to subtract the experimental value (12.8) by the actual volume (12.4) which equals 0.4. Then you divide 0.4 by 12.4 which equals 0.0322580645161 then you mutiply this by 100 which equals 3.22580645161 then you round this to the nearest tenth which is 3.2