1. Graph the following demand schedule. Complete the chart by first inserting the formula for the coefficient of price elasticity of demand. 
    Calculate elasticity of demand and show the three levels of price elasticity of demand on a graph.

Price	Quantity
20	1000
30	800
40	600
50	400

2. Draw both a perfectly elastic and perfectly inelastic demand curve. Give an example of each and state the characteristics that determined their elasticity.