Answer: This is a case of incomplete dominance inheritance because we can asume that the tail length is a trait with 2 alleles (no tail and long), but is posible to see 3 fenotypes, long, no tail, and medium which can be consider as a half way between long and no tail.
The phenotypes that seem a mix of two traits have heterozygous genotype, in this case the two parental cats have genotype Ll (assuming L as the symbol for long tail) since they have medium tails
When 2 heterozygous individual cross, the proportions according to Mendel's laws is:
25% offspring: Homozygous dominant
25% offspring: Homozygous recesive
50% offspring: Heterozygous
This proportions are quit similar to those obtained in the exercise
2/11 = 18 % Long tail: LL
3/11 = 27% No tail: ll
6/11 =54% Medium tail: Ll
