Joshua drives from his home at 12pm to the court to meet his client. After he drives the first 5 miles in 6 minutes, he realizes that the car is low on gas. So he spends 10 minutes to fill up at a gas station. Once he leaves the gas station, he realizes that he will be at the court 15 minutes early if he drives at the sane speed as before. Since he doesn't want to arrive at the court more than 10 minutes early, he decreases his speed by 10 miles per hour for the rest of the way to the court and arrives 9 minutes early.