To Mr. Erickson
Regarding the solution of Haunted Purple, we, CWSA (Children With Special Abilities) class students - year 8 at Monrad Intermediate, Palmerston North, New Zealand.

The ratio of velvet violet to abyss blue to midnight black is 3:2:1 i.e. for 3 cans (litres) to 2 cans (litres), 1 can (litres), to make 6 litres. However, only 3 litres of Haunted Purple needs to be made. Therefore the proportions will have to be halved completely.

So
1 1/2 cans of vevet violet
1 can of abyss blue
1/2 can of midnight black

will make 3 litres of Haunted Purple.

We also have to use 1 can of gooey grape in the mixture and 2 litres of it is made by using 1 can of velvet violet and 1 can of midnight black. Only one can will be needed and it will consist of 1/2 can of velvet violet and 1/2 can of midnight black. So there is no need for the extra half can of velvet violet and the half can of midnight black that was in the first mixture because it is already included in the gooey grape.

So now there is
1 can velvet violet
1 can abyss blue
and 1 can goeey grape

to make three litres of Haunted Purple.