This question has to be solved using inequalities with the means of a graph. But despite breaking my head on it several times, I am unable to reach a viable solution.

"A supermarket sells two kinds of washing powder, Sure-clean and Quick-Wash. At least three times as much Sure-Clean is sold as Quick-wash. The supermarket has, at most, 1800cm^2 of shelf space for washing powders. A box of Sure-Clean requires 25cm^2 of shelf space, whilst a box of Quick-wash requires 15cm^2. The profit per box is 8p for Sure-Clean and 12p for Quick-Wash. How many boxes of each kind of powder should be stocked for maximum profit? What is the maximum profit?"

Please help me setup the inequality. I can handle the graphing and finding the solution for the inequality.

Thank you