Source - Welker - http://www.econclassroom.com/wp-content/uploads/2011/12/ElasticityPractice.pdf
http://www.econclassroom.com/wp-content/uploads/2011/12/PEDQuiz-newsyllabus.pdf
image: https://courses.byui.edu/econ_150/econ_150_old_site/images/4-2_Other_Elasticities_03.jpg