not understanding the formula for price elasticity of demand. did the first part of table correctly but when I go to the second part, the math doesn't work. P=1.00 QTY Dem 300 TR=300 .... Next P=.90, Q=.80 Qty Dem 400, TR 360... What is the Elasticity coefficient? 2.71 then P=.8, Q=500, TR=400...What is the Elasticity coefficient? ______ Next P=.7, Q= 600, TR=420... WHat is the Elasticity Coefficient?____________ etc....