Accounting professors earn more than English professors at most universities. Explain this with a supply and demand graph.

I will assume here (since I don't have more information) that each school needs one English and one Accounting professor, but that more people are ready to teach English than accounting (this assumption might be wrong, but it's what think)

therefore the supply is bigger for the English professors than for the Accounting professors - this means that the accounting professors can ask for bigger salary (the bigger the supply, the smaller the prize)