A consumer considers the choice of consumption bundles ( x, y ) which are made up of two goods: books (x) and pens (y).

a.) Write the general definition of the consumer's budget constraint.

b.) Write the budget constraint when Px= 20, Py= 4, and I = 80.

c.) Draw the budget constraint when Px = 20, Py= 4, and I= 80 in a clearly labeled (axes, intercepts) graph.

d.) Label at least 3 affordable bundles on your graph. Label at least 3 unaffordable bundles on your graph.

e.) What happens to the collection of affordable bundles if Py increases from 4 to 8? Draw this change, and give a new equation for the budget constraint.