The issue between Nick and John is that does the fact enable John to claim the additional $1000?
According to the fact, It is from the Australian case of William v Roffey Brothers & Nicholls. This case is concerned with the defendant agree to pay extra bonus to the plaintiff if he can finish work on time.
The issue for the plaintiff John is under the rules of consideration where said that a promise of extra payment might be enforceable if it made by a promisor.
In William v Roffey Brothers & Nicholls case, the court held that William permitted to payment. William was enforceable to obtain a bonus due to Roffey received practical benefit in term of working relationship between William and Roffey.
Similarly, in the original contract between Nick and John was John need to provide catering facilities at the rally at the cost of $5000, due to make sure everything run smoothly Nick agreed to pay extra $1000 bonus to John. However, in the case Stilk v Myrick might show that the performance of an existing contractual duty will not provide good consideration for a promise. In this case John did not require any extra charge during his work, but Nick provided it to him. Moreover, the benefit under the working relationship between Nick and John had taken by Nick. As a result, this probably lead to the sufficient consideration, John was entitled to be paid the additional $1000 from his work.
Hence, the facts above indicate that the promise to make a bonus payment between Nick and John is an enforceable contract. By doing this, Nick probably need to reimburse to John in order to avoid breach of the promise.
Question B: Nick and Police
The issue in the situation between Nick and police is that can the police authority has an adequate consideration to claim $3000 for an additional protection on the open-air rally from Nick?
The facts are from the case of Glasbrook Bros v Glammorgan County Council where Glasbrook Bros asked police protection in from of officers quarters on the premises in order to avoid the potentially violent situation. After the strike was over, the collier owner denied to pay what it owed to the police.
The case of nick and police regarded to a contract issue of the consideration of the promise. As the rule of contract law, if a person is performing an existing duty which is already owed does not constitute consideration. However, if the promise provided additional beyond the duty of the contract then the original contract will be invalid, and it might lead .to an adequate consideration.
In Glasbrook Bros v Glammorgan County Council case the court held that the police were entited to be paid. Police authority already have a legal obligation to provide protection to society without being paid anything. However, if the police duty is going beyond what the collier owner expected to do, then it might be a good consideration. Therefore, the contract was enforceable, and the police could recover the amount of charge.
Similarly, in this case, nick asked police for additional protection on the open-air rally and he agreed to pay $3000. Police officers already have a legal obligation to provide protection to society, as a result this is not a good consideration. However, police had added an extra protection which requested from Nick under the agreement to paid $3000. As a result, Nick have to pay to the police as the amount he promised for additional protection.
According to the fact, it indicates that there is a good consideration between Nick and police. Hence, Nick might need to pay the police $3000 as a promise.
Question C: Nick and Hanson
The issue for this fact is that should Nick repaid the fully amount for the service of flying an aircraft over the rally back to Hanson?
This fact bears a remarkable similarly to the case of Roscorla v Thomas which is concerned with Roscorla who asked Thomas for the horse’s assurance after they had completed their contract.
The problem of Nick and Hanson is under the case of past consideration due to the promise between Nick and Hanson were made after Hanson had already done.
In case Roscorla v Thomas the court held that since the contract between two paties had been already concluded when the promises were made then Thomas’s promises were not supported by consideration. As a consequence, Roscorla had given no consideration for the subsequence promise and thus, it was enforceable.
Likewise, in this case the Nick promised to reimburse Hanson fully in due course after the flying aircraft had done under the oral agreement that Hanson provide the service free of charge for Nick. However, there is one major exception in this rule is the promisor must have requested the promise to perform the act the promise might become enforceable as shown in the case Lampleigh v Braithwait. Unfortunately, in this case Hanson seems to be unlikely to succeed as it offered to perform the act rather than being asked by Nick and Hanson obviously offered the service without payment. Thus, Hanson might be unable to be remunerated the fully course.
Correspondingly, the fact indicates that the contract between Nick and Hanson is the past consideration. Nick possibly does not need to reimburse to Hanson.
Question D: Nick and Ian
The issue between Nick and Ian is that can Nick legally claim money back from Ian as Ian agreed to pay Nick $10000 to help with expenses.
The facts are from the case of Combe v Combe. The case concerned with the wife force her husband to pay the maintenance he promised to pay, and she argued that husband should be estopped from resiling from that promise since she had acted on it.
The problem between Nick and Ian relates to promissory or equitable estoppel. The rule of estoppel is that if one party induced another to act in a certain way he/ she might subsequently be prevented from denying that fact.
In Combe v Combe, it was held that the wife enforced to claim for the money if her husband had given consideration to her. However, the court found that Mrs. Combe had given no consideration to her husband. Thus, it does not alter the rule that consideration is necessary in all contracts.
Similarly, in this fact it may be true that Nick truly have an writing agreement with Ian because he believes that his organized an open-air rally possibly helped by the fund promised by Ian as $10000 due. Moreover, Ian did not gain a benefit from his promised to support Nick $10000, he did it for free and although, it might be some factual illegal advantage for Ian. There is no legal benefit as they have a pre-existing contractual right to full payment. Thus, Nick provided no consideration to Ian for claim $10000.
Accordingly, the fact indicates that Nick could not claim $10000 from Ian due to Nick provided no consideration to Ian.
Fitzpatrick, Jefferey F et al, Business and Corporations Law (LexisNexis Butterworths, 3rd ed, 2017)
  1 QB 1.
 J.F. Fitzpatrick, C.F. Symes, A. Veljanovski & D.Parker, Business and Corporations Law 3rd Edition (Lexis Nexis Butterworths: Australia: 2017) p. 160.
 Williams v Roffey Brothers & Nicholls (Contractors) Ltd  1 QB 1.
 (1809) 2 Camp 317
  AC 270
 J.F. Fitzpatrick et el (op cit n.2 above) p.159.
 (1842) 3 QB 234
 (1615) Hob 105
  2 KB 215.
J.F. Fitzpatrick et el (op cit n.2 above) p.165
 Ibid (n 9 above) pg 167.