A ban on single-use plastic coffee pod machines in offices will reduce the demand for compatible coffee pods. This is because:
consumers are irrational
consumers expect the price of coffee pods to rise
the goods are complements
the goods are substitutes
119 exam-style questions on Edexcel A A Level Economics 1.2.3 Price, income and cross elasticities of demand. Each one has a worked solution and a mark scheme showing where the marks go.