Aspect of contract of negligence for business

Scenario:  This scenario continues, as before, in Assignment Brief B.  You are working as a legal assistant for one of the senior partners in a local firm of solicitors.  They have asked you to consider the following case studies and to prepare a report for each one.  Your reports will require you to consider each set of circumstances and to express your recommendations, based on your knowledge of UK law.
Case study 3  
3. Adam advertises a reward of £1,000 for the first person to paddle across the English Channel in a bath, from Dover to Calais. Brian sees the advertisement in the news paper, purchases a bath, and sets out from Dover. On the same day, whilst Brian is in mid-channel, Adam places another advertisement in the same news paper announcing that the reward is being withdrawn with immediate effect. Unaware of this, Brian continues his voyage and duly arrives in Calais. Brian then claims the reward. Adam refuses to pay.
Task 3:  LO3 (LO 3.1, LO3.2, LO3.3), M2, D2
Is Brian entitled to claim the reward? Taking this scenario into consideration, contrast liability in tort with contractual liability.  Explain the nature of liability in negligence and explain how a business can be vicariously liable.
To achieve M2, the learner will be using the given business scenarios to apply the law on terms in different contracts while evaluating with evidence of two or more sources of information for each legal point in the assignment.  To achieve D2, the learner will demonstrate the qualities of managing and organising responsibility in order to carry out activities.