We have: .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, 1800cm² of shelf space for washing powders.
A box of Sure-Clean needs 25cm² of shelf space; a box of Quick-wash needs 15cm².
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?
We are also told that: .
And we have: .
. . Go for it!