Can you answer this for me please. Using ILAC method

Question 2 Tim advertises in the local paper that he has lost his wallet and offers a reward of $500. Tom who has not read the advertisement find the wallet and returns it to Tim. He later finds out that there is a reward for the return of the wallet, and asks Tim for the reward claiming that he had showed acceptance by returning the wallet. Tim refused to pay the reward and so Tom sued Tim for breach of contract. Explain with reference to the Acceptance element whether Tim is obliged to pay the reward. Would it be different if Tom knew of the reward before he found Tim's wallet