All other things being equal, when the equilibrium price of wireless headphones in a market rises from £40 to £50, the quantity demanded falls from 5 million units to 3 million units. Therefore, the value of the price elasticity of demand is
−1.6-1.6−1.6
−0.625-0.625−0.625
+1.6+1.6+1.6
+0.625+0.625+0.625