The extended demand function of good X is:

QDX = 1400 - 20 PX - 10 PY + 0.1 M where:

QDX = quantity demanded of good X

PX = Price of good X

PY = Price of related good Y (related in consumption to good X)

M = Average consumer income .

Fix the following variables:

M = 10,000

PY = 50,

Assume:

PX changes from $50 to $60

What is the absolute value of the price elasticity of demand [Use the arc elasticity formula.]