Each month, an airline sells 1,500 business-class tickets from London to Paris at $200 a ticket, and 6,000 economy-class tickets at $80 a ticket.

Each month, an airline sells 1,500 business-class tickets from London to Paris at $200 a ticket, and 6,000 economy-class tickets at $80 a ticket. Use this information to construct the demand curves of business travelers and tourists respectively, if it is given that the demand curves for both groups are linear and that the marginal cost of a ticket is constant at $50. Please give the equations for the demand curve as well.