A train takes 18 seconds to pass completely through a station 162 m long and 15 seconds through another station 120 m long. The length of the train is :
Answer & explanation
Correct answer: option 3
Speed = \(\frac{ Distance}{ Time}\)
Let the length of the train be x
According to the question,
Speed = \(\frac{\text{x + 162}}{ 18}\) -------1st equation
Speed = \(\frac{\text{x + 120}}{ 15}\) -------2nd equation
Therefore, we can say that:
\(\frac{\text{x + 162}}{ 18}\) = \(\frac{\text{x + 120}}{ 15}\)
\(\frac{\text{x + 162}}{ 6}\) = \(\frac{\text{x + 120}}{ 5}\)
5x + 810 = 6x + 720
x = 90
So, the length of train is 90 m