Question

1. Mario borrowed a rare vintage car from his friend, Juan, for a weekend drive. During the drive, Mario got into an accident which caused significant damage to the car. Mario was unable to pay for the repairs, so Juan had to shoulder the expenses. Juan believes that Mario should be held responsible for the costs incurred due to the damage caused by his negligence.

Determine whether Juan can pursue a case of unjust enrichment against Mario based on the given facts and relevant laws. Explain the basis for your answer and discuss the elements that need to be proven to establish unjust enrichment.

2. Ana mistakenly transferred a substantial amount of money to the account of her colleague, Carlos. Ana contacted Carlos to rectify the error and requested the return of the transferred amount. However, Carlos refused to return the money, claiming that Ana's mistake is not his fault and that he is entitled to keep the funds. Ana argues that Carlos should be obliged to return the money based on the principle of unjust enrichment.

Analyze whether Ana's claim of unjust enrichment is valid in this situation. Discuss the necessary elements that Ana needs to prove to succeed in her claim, as well as any possible defenses that Carlos may raise.

3. Maria hired Pedro to renovate her house. They agreed on a contract stating that Maria would pay Pedro a certain amount upon completion of the renovation. However, after Pedro completed the work, Maria refused to pay him, claiming that the renovation was not up to her standards and that she should not be obligated to pay for subpar work.

Explain whether Pedro can invoke the principle of unjust enrichment to demand payment from Maria. Discuss the elements that Pedro would need to establish to succeed in his claim, and consider any possible defenses that Maria may raise.