Car A leaves the airport at 8:00 am and travels at a constant rate of 40 km per hour. Car B leaves the airport at 8:15 am and travels in the same direction along the same highway at a constant rate of 46 km per hour. At what time will Car B be 11 km ahead of Car A?  Choose the correct choice from the following answers.
A) 10:45 am
B) 11:00 am
C) 11:15 am
D) 11:45 am
E) 12:15 pm
At 8:15 am, Car A will be 10 km ahead of Car B.   Car B travels at a rate 6 km per hour faster than Car A.   Car B needs to travel 21 km more than Car A in order to be 11 km ahead.   This will take 21 km/6 km per hour=3.5 hours.   Car B will be 11 km ahead at 11:45 am.   The answer is 11:45 am.
<result>D</result>
Car A leaves the airport at 8:00 am and travels at a constant rate of 40 km per hour. Car B leaves the airport at 8:15 am and travels in the same direction along the same highway at a constant rate of 46 km per hour. At what time will Car B be 11 km ahead of Car A?