It seems okay to me (if that what your asking) I don't know this subject very well ut the part your working on " I'm familiar with ?" Don't be surprised if I was wrong buuuuut it does look okay to me "(the answer)".
You subtract 3 miles from the 5.5 miles which gives you 2.5
<span>A would be 6/7 x 28kg = 24 kg
B would be 4/7 x 28kg = 16 kg
so the difference of the masses is 24 - 16 = 8kg</span>
