total sugar=number of containters filled times sugar per container
convert each to a/b form to multiply easier since

2 4/5=2+4/5=(2*5)/5+4/5=10/5+4/5=14/5
3 2/7=3+2/7=(3*7)/7+2/7=21/7+2/7=23/7
total sugar=number of containers times sugar per container
total sugar=2 4/5 times 3 2/7
total sugar=(14/5) times (23/7)
total sugar=(14*23)/(5*7)
total sugar=322/35
total sugar=35/35+35/35+35/35+35/35+35/35+35/35+35/35+35/35+35/35+7/35
total sugar=1+1+1+1+1+1+1+1+1+7/35
total sugar=9+7/35
total sugar=9+1/5
total sugar=9 1/5 tons