Both SmithCo and Jones Inc. sell widgets. SmithCo's sales last month equalled 1000 and it charged a price of $2. This month Jones Inc. reduced the price it sells its brand of widgets from $2.10 to $2, and SmithCo saw a reduction in the quantity of widgets is sold, down to 900 units. What is the cross elasticity of demand between the two brands of widgets? (Use the midpoint method described in equation 3.14).