Consider the demand for coal with quantities in tons. When the price of coal decreases from $60 to $50, the quantity of coal demanded increases from 400 to 500 tons. Similarly the price of coal increases from $70 to $90, the quantity of coal demand decreases from 300 to 100 tons.
Using the midpoint formula, when price decreases from $60 to $50, the price elasticity is?
Using the midpoint formula, when price increases from $70 to $90 the price elasticity of demand is?