Question 1059087
This could be better understood solving in two parts.  First, what is the amount of coal if the container were full?  Call this number, M.


Difference between twothirds full and five-twelths full is 300 pound difference.  See {{{925pounds-625pounds=300pounds}}}.


{{{(2/3-5/12)M=300}}}-----main starting equation.


{{{12(2/3-5/12)M=12*300}}}


{{{(8-5)M=12*300}}}


{{{3M=12*300}}}


{{{highlight(M=1200)}}}------the weight of just the coal IF container were full.



<u>SECOND PART</u>


How much coal is in the {{{2/3}}} full container?

{{{(2/3)*1200=800*pounds}}}-----The reason that the container with the coal is heavier is, that the container AND the coal weigh more than just either of them alone.


{{{ContainerWithCoal-JustTheCoal=JustTheContainer}}}


{{{925-800=125}}}
The container alone weighs 125 pounds.