c) PU Pet Snacks priced its product at $1.22. The marketing department noticed that the average household income of the Pet Snacks consumers increased from $15,100 to $15,780 over a one vear period. During this time the average sales of Pet Snacks increased 179 boxes. Determine the income elasticity of PU Pet Snacks. d) During May, Milkbone brand increased its price from $2.00 to $2.25. The average weekly sales of PU Pet Snacks increased by 399 boxes. Determine the cross elasticity of PU Pet Snacks and Milkkone brand