What is the life expectancy of a black and tan coon-hound/rottweiler?

while there is no certain or specific for this ques as its a mix, but going by the breed clification, they both come in large breeds i guess, not so sure about coon hound i mean, rott i kn come in large/giant breeds, so looking at it practically, 15 would be stretching it too far, say roughly 8-12 years. Give it best diet acc. to its age/weight n u'll prolong its life some time more too.... end is sad but thats life..