With demand and supply curves- if the price is $10, the quantity
demanded is 500 and the amount supplied is 50, which amount - the 500
or the 50  is what is consumed?

From that, how do you determine of that amount what is produced
domestically and what part is imported

This sounds very much like a homework problem so I (and probably the
researchers) will not answer it... however here is a bit of guidance:

It sounds like the entire situation is not explained.  
"the amount supplied is 50" 
"determine of that amount what is produced domestically and what part is imported"
So... Is the 50 the total supplied (as stated) or is that the total
supplied domestically (and more can be supplied as imports)?  It seems
the information provided isn't enough to determine what part of either
of those would be provided domestically vs imported.

Keep in mind while answering your question that only the amount that
exists (perhaps less but never more) can be consumed.

Best of luck with the answer!