Q:

A) 250 mts | B) 400 mts |

C) 320 mts | D) 390 mts |

Answer: B) 400 mts

Explanation:

Explanation:

Let the length of the 1st train = L mts

Speed of 1st train = 48 kmph

Now the length of the 2nd train = L/2 mts

Speed of 2nd train = 42 kmph

Let the length of the bridge = D mts

Distance = L + L/2 = 3L/2

Relative speed = 48 + 42 = 90 kmph = 90 x 5/18 = 25 m/s(opposite)

Time = 12 sec

=> 3L/2x25 = 12

=> L = 200 mts

Now it covers the bridge in 45 sec

=> distance = D + 200

Time = 45 sec

Speed = 48 x5/18 = 40/3 m/s

=> D + 200/(40/3) = 45

=> D = 600 - 200 = 400 mts

Hence, the length of the bridge = **400** mts.

1
465

2
460

Q:

A) 2 hours | B) 6 hours |

C) 3 hours | D) 4 hours |

1
391

0
412

Q:

A) 245 and 54 | B) 255 and 40 |

C) 255 and 36 | D) 245 and 45 |

0
406

Q:

A) 5.76 m/s | B) 7.76 m/s |

C) 6.76 m/s | D) 4.76 m/s |

0
384

1
368

Q:

A) 140 km/h | B) 105 km/h |

C) 70 km/h | D) 280 km/h |

0
405