1) Trains are running with speeds 30 km/h and 58 km/h in the same direction. A man in the slower train passes the faster train in 18 sec. The length in meters of the faster train is A) 70 m B) 100 m C) 128 m D) 140 m E) 158 m Answer: Option DExplanation:Relative Speed $=58-30$ $=28$ km/h $=28\times\frac{5}{18}$ m/sec $=\frac{70}{9}$ m/sec Length of the train $=\frac{70}{9}\times 15$ = 140 m
