if you breed a pure whippet to a pure greyhound the pups would be half crosses as in half whippet and half greyhound now if you put a whippet back to one of these dogs the pups would be 3/4 whippet 1/4 greyhound or if you used a greyhound the pups would be 3/4 greyhound 1/4 whippet hope this helps