Let the total distance be 2D km, then

Total time = Time taken by train + Time taken by car =

Therefore, Average speed=

=

A) 1.78 kmph | B) 2.35 kmph |

C) 2.83 kmph | D) 3.15 kmph |

Explanation:

Given speed of the person = 8 1/2 = 17/2 kmph

Let the speed of the stream = x kmph

speed of upstream = 17/2 - x

speed of downstream = 17/2 + x

But given that,

2(17/2 - x) = 17/2 + x

=> 3x = 17/2

=> x = 2.83 kmph.

A) 41.25 days | B) 37.5 days |

C) 39.75 days | D) 40 days |

Explanation:

Given Karthik can cover the distance of 200 kms resting 2 hrs per day in 22 days.

Let the initial speed be '1'

Hence, Time = 22(24hrs - 2)

Noe new speed = 2/3

Let the number of days he take be '**D**'

Therefore,

D = 11 x 3 x 5/4 = **41.25 days**. = 41 1/4 days.

A) 85 km/hr | B) 95 km/hr |

C) 105 km/hr | D) 120 km/hr |

Explanation:

Initial speed = 80km/hr

Total distance = 80 x 10 = 800km

New speed = 800/4 =200km/hr

Increase in speed = 200 - 80 = 120km/hr

A) 38 kmph | B) 40 kmph |

C) 60 kmph | D) 54 kmph |

Explanation:

Average speed = Total distance / Total time.

Total distance traveled by Joel = Distance covered in the first 3 hours + Distance covered in the next 5 hours.

Distance covered in the first 3 hours = 3 x 60 = 180 miles

Distance covered in the next 5 hours = 5 x 24 = 120 miles

Therefore, total distance traveled = 180 + 120 = 300 miles.

Total time taken = 3 + 5 = 8 hours.

Average speed = 300/8 = 37.5 mph.

we know that 1 mile = 1.6 kms

=> 37.5 miles = 37.5 x 1.6 = 60 kms

Average speed in Kmph = 60 kmph.

A) 54 sec | B) 36 sec |

C) 72 sec | D) 11 sec |

Explanation:

Time taken to meet the first time = length of track/relative speed

Given the length of the track is 600 m

The relative speed = 25 + 35 = 60 kmph = 60 x 5/18 m

Therefore Time = = 600/60 x (18/5) = 36 sec.