Final answer:
John may have a case against KenMart if he can establish that their negligence directly contributed to his slip and subsequent injury.
Step-by-step explanation:
Whether or not John can pursue a legal case against KenMart, the supermarket, depends on the circumstances surrounding his accident. Generally, to establish liability, John must prove that KenMart owed him a duty of care, there was a breach of that duty, and this breach caused his injury. In this case, KenMart has taken some precautions by placing a wet floor sign and having a cleaning schedule, which demonstrates that they were aware of the potential hazard and took steps to mitigate it. However, if it can be shown that KenMart's actions were negligent (e.g. failing to adequately clean the floor or failing to repair a known issue), and this negligence directly contributed to John slipping and breaking his arm, then he may have grounds for a personal injury claim.
It is important to note that the outcome of a potential case would depend on the specific facts and circumstances, as well as the applicable laws in Sydney, NSW. To evaluate if John has a strong case, it would be advisable for him to consult with a personal injury lawyer who can assess the details of his situation and provide appropriate legal advice.