Answer:
A) the price elasticity of demand (PED) of Jessica's buffalo wings is:
PED = % change in quantity / % change in price
{Q2 - Q1 / [(Q2 + Q1) / 2]} / {P2 - P1 / [(P2 + P1) / 2]} = {500 - 300 / [(500 + 300) / 2]} / {3.50 - 2.50 / [(3.50 + 2.50) / 2]} = (200 / 400) / (1 / 3) = 0.5 / 0.33 = 1.52
B) $3.50 x 300 = $1,050
$2.50 x 500 = $1,250
A price of $2.50 per buffalo wing order will result in a total revenue of $1,250
C) Cross PED = % change in quantity demanded for Product A / % change in price of product B.
% change in quantity demanded of widgets / % change in price of wings = 20% / 10% = 2
Since the cross PED of widgets and wings is positive, then they are substitute products.
D) PED measures the proportional change in quantity demanded when the price of the product changes by 1%, while the slope of the demand curve measures the change in price due to a change in the quantity demanded.
Both concepts seem to be similar, their definitions include too many price changes and changes in the quantity demanded, but they measure different things. One measures a change in units and the other a change in price.