I honestly have no idea how to even go about solving this problem. If someone can give me a hint, that'd be great.
Start by understanding what the problem is saying. You have a Leontief model of the form
[tex]\textbf{x} = C \textbf{x} + \textbf{d},[/tex]
where d is external demand and C is the inter-sector internal demand matrix. The question is asking if it is OK to have cii > 1 for some i, and if not, why not.
It asks for both mathematical and real-world reasons.
I have read about the Leontief model but I still don't know how to answer the question. I think you should be able to have numbers greater than one along the diagnol