The masses of two bodies are measured to be 15.7 ± 0.2 kg and 27.3 ± 0.3 kg. What is the total mass of the two and the error in it?

 

The masses of two bodies are measured  to be 15.7 ± 0.2 kg and 27.3 ± 0.3 kg.  What is the total mass of the two and the  error in it?