Recessive epistasis

I've just taken a genetics quiz which I can take over and over until I get above 90%. There's one question I'm having trouble with. I finally got the answer right, but I don't understand why.

Here's the question:

A locus in Australian Bearded Dragons is involved in the production of pigment. When heterozygous parents mate, 75% of the progeny are colored and the rest are albino. [This tells me that aa = albino.] Another phenotype concerns the specific colors that are expressed such that when two green bearded dragons mate, 2/3 of the progeny are green and the rest are speckled green and purple. The albino dragons cannot express whatever alleles they may have that determine specific color.

When a certain line of green dragons is crossed with a certain line of albino dragons, half of the progeny were green and the other half were speckled green and purple. The green progeny were allowed to interbreed, and 24 eggs were produced. How many of each possible phenotype would you expect to see after they hatch?

How many albinos?
How many greens?
How many speckled?

I know that the answer is 6, 12, 6, respectively, but I don't know why. I can't figure out what the green genotype is.

And I know that the inheritance pattern is an example of recessive epistasis (another quiz question, which I got right), but where is the 9:3:4 ratio that recessive epistasis should cause?

(The specific answer to the question about recessive epistasis is as follows: "The gene that determines whether or not color is expressed is recessively epistatic on the gene that determines the specific color.")

Thank you.