What is the value of y^-5/x^-3 for x=2 and u=-4

Jane is cooking beans and rice for dinner tonight. she has 4 cans of black beans, 6 cans of red beans, and 3 cans of garbanzo beans in her cupboard. if she grabs a can of beans without looking at the label, what is the probability of her making black beans and rice for dinner?