Question: two trains 250 m and 500 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time which they take to cross each other is ?
A) 10.6
B)  10.9
C) 10.4
D)  27
E)  10.1
Correct answer: d
Grade: 8 | Topic: Geometry | Difficulty: Easy | Standard: 8.G.B.8