I recently interviewed for a Cambridge college as part of the undergrad admissions process and one of the questions I asked was as follows:

“We have a scenario where two shops (e.g. supermarkets) are selling the same product (e.g. chocolate bar) at the same price, does this necessarily mean that collusion is occurring? What other factors might the authority want information on?”

I find this to be an interesting question, as there isn’t a right or wrong answer and so it allowed applicants to discuss a wide range of economic phenomena, from market structure to pricing decisions and I wanted to elaborate upon a few of these points here. [...]