A car traveling at a certain constant speed takes 15 seconds longer to travel 1 kilometer than it would take to travel 1 kilometer at 60 kilometers per hour. At what speed, in kilometers per hour, is the car traveling?
Choose the correct choice from the following answers
A) 48	B) 50	C) 52	D) 54	E) 56

Rationale: "60 * t = 1 km = > t = 1 / 60 km / h v * ( t + 15 / 3600 ) = 1 v ( 1 / 60 + 15 / 3600 ) = 1 v ( 75 / 3600 ) = 1 v = 48 km / h the answer is a ."
Answer: A