Damien sent a letter to his cousin Roger who lived on a farm offering to sell him his ride on lawnmower for $500 (it was valued at $2000). Roger received the letter and immediately wrote a letter accepting the offer and put the letter in the mailbox when he went to town on Monday the 1st of August. On Wednesday the 3rd of August Damien was talking to his friend Colin and mentioned that he was trying to sell his ride on lawnmower as he no longer needed it. Colin offered to buy it for $700 and Damien accepted. Colin gave Damien the $700 and Damien said he would arrange for delivery the next day. That afternoon Damien received the letter from his cousin Roger which said he was happy to buy the mower for $500. Advise Roger, a) Does he have a legally enforceable contract b) What are the principles of law that are relevant in this case? c) Are there any cases that assist your arguments?