Arjun, at the request of the local community leader, builds a playground for the children in his neighborhood, spending a considerable amount of his own money. Later, Ravi, a local snack vendor, sets up a stall near the playground to sell snacks to children and promises to give Arjun 10% of his profits from all sales as a token of appreciation for building the playground. However, Ravi fails to pay Arjun the promised percentage, and Arjun decides to take legal action to recover it.
Based on contract law principles, which of the following is correct?