linear programing graphical solution problem

hey guys...

i have a question and not able to find the equations to solve the problem... please help... its urgent....

Solve the problem graphically to find the maximum value of the profit and the optimal values of the decision variables.

For one of its clients, Propaganda Ltd. must run a series of advertisements on television for one week, for which there are two tariffs: off-peak and peak (prime-time). There is a budget of £100,000 available for the advertising.

Off-peak advertising costs £750 per minute and generates a revenue of £1,200 per minute.

Prime-time advertising costs £5,000 per minute and generates a revenue of £7,000 per minute.

The rules of the broadcaster mean that the company must buy at least one hour of off-peak advertising.

What mix of daily prime-time and off-peak advertising should Propaganda Ltd. buy in order to maximise profit, and what is the maximum profit? **(NB: Profit = Revenue – Cost)**

Solve the problem graphically to find the maximum value of the profit and the optimal values of the decision variables.