From an island, it is possible to reach the mainland by either Ferry P or Ferry Q. Ferry P travels for 3 hours at 6 kilometers per hour, while Ferry Q takes a route that is three times longer. If Ferry P is slower than Ferry Q by 3 kilometers per hour, how many hours longer is the journey of Ferry Q compared with the journey of Ferry P? Select the correct option: A) 1 B) 2 C) 3 D) 4 E) 5

Rationale: "the distance traveled by ferry p is 18 km . then the distance traveled by ferry q is 54 km . ferry q travels at a speed of 9 kph . the time of the journey for ferry q is 54 / 9 = 6 hours , which is 3 hours more than ferry p . the answer is c ."
Answer: C