can anyone help start this I got this question wrong and i d

can anyone help start this? I got this question wrong and i dont know why

Pure dog breeds Z and Q have very short legs. When Z or Q dogs are crossed to a normal breed (Z x normal, or Q x normal), the F1s have long legs, but short-legged dogs are found in 1/4 of the F2s.

A Z dog is crossed to a Q dog. All F1 pups have long legs. What is the probability of short-legged dogs in the F2?

Solution

Half of the individuals in F2 will be short legged. In the presence of both Z and Q dogs will be short legged. In normal dogs either it should be zzQQ or ZZqq . in presence of Z and Q it will be short legged. Hence when crossing Z and Q half the individuals are long legged and half are short .