Tyson Chicken produces both thighs and wings. When it produces 150 thighs and no wings, its total cost is $600. When Tyson produces 150 wings and no thighs, its total cost is $400. And when Tyson produces both 150 thighs and 150 wings jointly, its total costs are $900. 

a. Show that, for an output level of 150 thighs and 150 wings, Tyson experiences economies of scope.

b. What is the likely source of Tyson’s economies of scope?