David drives from his home to the airport to catch a flight. He drives $35$ miles in the first hour, but realizes that he will be $1$ hour late if he continues at this speed. He increases his speed by $15$ miles per hour for the rest of the way to the airport and arrives $30$ minutes early. How many miles is the airport from his home? (2014 AMC 10A Problems, Question \#15) 
选项为:A:$$140$$  B:$$175$$  C:$$210$$  D:$$245$$  E:$$280$$  请回答其中一个选项.