Ratio of speeds of A:B = 1000:900 = 100:90

Ratio of speeds of B:C = 1000:920 = 100:92

Therefore, when A moves 1000m , B moves 900 m and when B moves 900m, C moves 828m

Thus,

Since , C moves 8 % less than B in the same time . Thus, C is the worst performer and A will win by him by 172 m

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.

A) 1.8 kmph | B) 2 kmph |

C) 2.2 kmph | D) 1.5 kmph |

Explanation:

Speed of Boy is B = 4.5 kmph

Let the speed of the stream is S = x kmph

Then speed in Down Stream = 4.5 + x

speed in Up Stream = 4.5 - x

As the distance is same,

=> 4.5 + x = (4.5 - x)2

=> 4.5 + x = 9 -2x

3x = 4.5

x = 1.5 kmph

A) 4.58 kms | B) 6.35 kms |

C) 5.76 kms | D) 5.24 kms |

Explanation:

Speed in still water = 6 kmph

Stream speed = 1.2 kmph

Down stream = 7.2 kmph

Up Stream = 4.8 kmph

x/7.2 + x/4.8 = 1

x = 2.88

Total Distance = 2.88 x 2 = 5.76 kms

A) 55 kmph | B) 58 kmph |

C) 60 kmph | D) 66 kmph |

Explanation:

Speed on return trip = 150% of 50 = 75 km/hr.

Average speed = (2 x 50 x 75)/(50 + 75) = 60 km/hr.