how can i solve this question , with steps ?

Consider the following alternate#2 Hypothetical Chronology for Adams (A) v Lindsell (L): Sept Sept 5 8 Sept 2 L mails offer letter to A L's offer letter is received by A, who immediately posts L receives A's acceptance Letter Sept 9 L sells goods to a 3rd party stipulating acceptance "by acceptance letter notice in writing" Key Questions: Q1. On what date, if any, would a contract have been formed? How do you know? Q2. On what date, if any, would BoC have taken place? How do you know