Lucy makes green paint by mixing yellow and blue paint in the ratio 5:2. Blue paint costs £30 for 5 litres and yellow paint costs £28 for 7 litres.
Lucy sells her green paint for £4.50 per litre. Will she make a profit? Show your working
to justify your decision.

No, she won’t make a profit

Step-by-step explanation:

Here, we are interested in determining if Lucy made a profit or a loss.

The cost of blue paint is 30 pounds for 5 liters. This means that a liter of blue paint is 30/5 = 6 pounds per liter

The cost of yellow paint is 28 pounds per 7 liters, the cost per liter is 28/7 = 4 pounds per liter

Now, in her mixing, she mixes 5 parts of yellow paint and 2 parts of blue paint.

This means that she mixed them the ratio as follows per liter;

For yellow, we have; 5/(5+2) = 5/7

For blue we have 2/(5+2) = 2/7

Now since a liter of yellow paint cost 4 pounds

5/7 of a liter will cost 5/7 * 4 = 20/7 pounds

For the blue paint, a liter cost 6 pounds, 2/7 of a liter will cost 2/7 * 6 = 12/7

The total cost in pounds in this;

20/7 + 12/7 = 32/7 = £4.57 pounds to 2 decimal place

Now she sells her green paint product at £4.5 per liter. Since this is less than the cost price of production which is £4.57, she is running at a loss