A 180 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train? Choose the correct choice from the following answers:
A) 320 meter
B) 225 meter
C) 230 meter
D) 235 meter
E) none of these

Rationale: "explanation : as trains are running in opposite directions so their relative speed will get added so , relative speed = 120 + 80 = 200 kmph = 200 * ( 5 / 18 ) = 500 / 9 m / sec let the length of other train is x meter then x + 180 / 9 = 500 / 9 = > x + 180 = 500 = > x = 320 so the length of the train is 320 meters option a"
Answer: A