Rewrite y=a(2)^1/3 in the form y=a(1+r)^t or y=a(1-r)^t. then state the growth or decay rate

At the "no mutants allowed" country farm, every sheep has 4 legs, every chicken has two legs, and all animals have only 1 head. asked to count how many sheep and chicken are in the fields, a farm boy reports back that there are 140 feet and 50 heads. how many sheep and chicken are there? there are sheep and chicken at the farm.