Last week, Collins went to a supermarket to buy a snack. In the supermarket, he picked up a packet of potato chips from the shelf. The price tag on the packet indicated that the price for the potato chips was HK$20.When Collins gave HK$20 to the cashier of the supermarket, the cashier told him that the price for the potato chips should be HK$40.Required:In relation to contract law, advise Collins as to whether he could insist on paying HK$20 for the potato chips. (10 marks)