A train 75 metres long overtook a man who was walking at the rate of 6 km/h and passed him in 18 seconds. Again, the train overtook a second person in 15 seconds. At what rate was the second person travelling ?  Choices
A) 3 km/h
B) 2.5 km/h
C) 4 km/h
D) 1.5 km/h
E) None of these
Let actual speed of train ST km/h.   Then, ST - 6 = 75⁄18 × 18⁄5 = 15   ⇒ ST = 21 km/h   Now, let speed of second man = Sm   21 - Sm = 75⁄15 × 18⁄5 = 18   ⇒ Sm = 3 km/h   3 km/hnswer 3 km/h
<result>A</result>
A train 75 metres long overtook a man who was walking at the rate of 6 km/h and passed him in 18 seconds. Again, the train overtook a second person in 15 seconds. At what rate was the second person travelling ?