Contract Law

Mark is an Australian citizen and a businessman residing in Australia. He offered to purchase Rob's house and gave Rob six weeks for a definite answer. Rob, on the basis of Mark's offer, bought another house. Before the six weeks expired, but after Rob had bought the second house, Mark withdrew his offer. In the course of running his business operations, Mark had been accustomed to dealing with Maddock, the owner of a shop with which he had a running account. Mark recently sent an order to Maddock's shop for the supply of some goods. The shop had that very day been sold to the foreman, Carey, who supplied the goods. Mark used the goods and, when he learned of the change of ownership, refused to pay for them, claiming that he had intended to deal with Maddock personally as he had a set-off (i.e., he was owed money by Maddock) with him. Mark has a son named Sam who is a teenager. Sam obtained a loan of money from Les by telling him that he was 19 years old when in fact he was only 16. Sam then defaulted on the repayments, and Les, brought actions in contract and tort against Sam to obtain repayment.

My question is

1.Is Mark entitled to withdraw his offer to purchase Rob's house?

2.Is Mark liable for the price of the goods owed to Maddock by reference to Boulton v Jones (1857) 157 ER 232 and other applicable legal authorities?

3.Advise Sam whether Les is likely to succeed in his actions.