John's home suffers damage when an old tree falls on his home during a storm. His roof has a large exposed hole above his living room. When looking through the newspaper, John sees the following add: "My name is Ali, and I perform home repair services, including fixing storm damage. I charge $25 per hour for labor, plus the cost of materials. I am available twenty-four hours a day, seven days a week. If you would like my services, please email me with the details of your project and I will be happy to work for you at your convenience."

John sends the following email to Ali on Dec 1^st: "My name is John, and I want you to repair damage to my roof caused by a fallen tree. I accept the terms of your offer, so I will pay you $25 per hour for labor, plus the cost of materials. Please arrive on Dec. 4^th."

On December 2^nd, however, Ali receives an offer for more profitable work. Ali then calls John on December 2^nd and tells John that he will repair the roof, but that he won't be able to do so until December 6^th and that he will charge $30 per hour.

Ali buys the necessary materials and shows up at John's home on Dec. 6^th. John is at home and tells Ali to get started. After Ali begins the work, however, he stops and refuses to perform any further unless John agrees to pay him $50 per hour. Ali says that, with all of the recent storm damage, his services are in demand, so the market price has increased. John grudgingly agrees on the condition that Ali will also replace a window that he just realized was also damaged. John agrees to the price increase only because the forecast calls for heavy rain soon, and he does not want further weather damage to his home. Ali agrees to replace the window at no additional cost.

When Ali is nearly complete, he receives an offer for more profitable work. Ali thus stops work on the project before the roof is repaired and leaves the work site. John attempts to hire someone else to finish the work, but cannot find anyone who is available on such short notice.

Two days later, a storm passes through, and John's home is flooded because the repair work was not completed. Soon thereafter, John hires Liam, who finishes the roof repair for $1,000. Because of the rain damage, John also has to pay Liam $500 to fix his flooring. Moreover, John had a collection of rare books in his living room that sustained over $50,000 in damages.

1. When was contract first formed between John and Ali, and what was the rate of pay?
2. Was the modification to the contract for a price of $50 per hour valid and enforceable?
3. How much money should John be awarded in damages from Ali's breach?