​​ PROBLEM Jen is organising a surprise party for her grandparents' 50th wedding anniversary. She looks online and finds 'Tiny Tim', a professional DJ who is just 17 years old. She emails Tim and asks him what he charges for his DJ services. Tim emails back the next day, providing a brochure listing different kinds of services he provides, at different rates. Jen then replies, saying:

'I am interested in booking a DJ for my grandparents' anniversary celebrations on 2rd April. Would you be available on that date? It looks like your 'weekend special' package would be most appropriate, because I expect the party to last about 4 hours. But what if we go beyond that time limit? And do you have a good collection of Cuban music? That is their favourite style of music.' Tim emails back: 'Yes, I have plenty of Cuban music, and I'm available on 2nd April. If you want me to stay longer than 4 hours, then I charge $30 per extra hour.' Jen does not reply to Tim, because she hears from a friend who is willing to provide DJ services for free. Jen wants to know whether she can change her mind about hiring Tim.

Jen also wants to arrange a cake for the party. On Sunday she goes into Delish Cakes, a local cake store, and speaks to the owner, Simon. Jen explains that the party is for her grandparents, and will have a Cuban theme. Simon suggests a particular style of cake, and Jen agrees that it would be perfect for the party. Simon says that he can specially make some Cuban-style fondant cake decorations. Jen is about to catch a train, so she doesn't have time to finish filling out the order form. She gives Simon her details and takes the order form with her, saying that she will return it to Simon in the next couple of days.

On Tuesday, Simon calls Jen. She doesn't answer, so he leaves a message, asking for the order form to be submitted. He also says that he will begin making the Cuban cake decorations. Jen listens to the message but doesn't call Simon back. Over the next couple of days she is too busy to complete the form and give it to Simon. By the end of the week, Jen is starting to worry that Simon's cake will be too expensive. On Friday she decides that she will simply make a cake herself. She calls Simon and tells him this. Simon is furious – not only has he spent hours making the Cuban decorations, but because they are unusual he will not be able to use them for any other customers' orders. Finally, Jen wants help in setting up the venue for the party. She sends a text message to her cousin: 'Hey Adam! I need you to spend a few hours helping me put up balloons and streamers for the party on Saturday.'

Adam replies 'Ok, I'll help you – but what's in it for me? What will you give me in return?' Jen texts him again: 'Remember how I helped you with your college assignment last month? That's the payment. It's time to return the favour.'

Adam is not convinced. Jen texts her other cousins, in case Adam doesn't turn up: 'Calling all cousins! If you come and help me prepare for the party on Saturday, I'll pay you $20.' Jen's uncle Bill sees the text message on his daughter's phone. He decides to help Jen set up for the party on Saturday, so he can get $20.

1. Is there an enforceable contract between Tim and Jen? 6 marks

2. Is promissory estoppel relevant to Jen's dispute with Simon from Delish Cakes? 5 marks

3. Is there an enforceable contract between Jen and Adam? 4 marks

4. Is Bill entitled to the $20 if he helps Jen set up for the party? 5 marks