CAT Practice : Speed Time, Races

A car trying to overtake a truck travelling the same direction should travel at some extra speed!! And that is equal to ---

Relative Speed

    Q.12: A car of length 4m wants to overtake a trailer truck of length 20m travelling at 36km/hr within 10 seconds. At what speed should the car travel?
    1. 12 m/s
    2. 14.8 m/s
    3. 12.4 m/s
    4. 7.6 m/s

 

  • Correct Answer
    Choice C. 12.4 m/s

Detailed Solution

Given :
car of length = 4 m
length of truck = 20 m
Speed of truck = 36 km/hr

Approach:
Total distance to be covered by the car 'd' = 20 + 4 = 24 m
Let speed of car be S1 m/s
Speed of truck S2 = 36 km/hr = 10 m/s
Both the car and the truck are travelling in the same direction and we know that to overtake the truck, the speed of the ca should be more than that of the truck.
Hence, relative speed = |S1 - S2|
Time to overtake = 10s

S =

|S1 - 10| =

S1 - 10 = 2.4
S1 = 10 + 2.4 = 12.4 m/s



Correct Answer: 12.4 m/s



Our Online Course, Now on Google Playstore!

2IIM's App

Fully Functional Course on Mobile

All features of the online course, including the classes, discussion board, quizes and more, on a mobile platform.


Cache Content for Offline Viewing

Download videos onto your mobile so you can learn on the fly, even when the network gets choppy!

Get it on Google Play
Visit Piverb.com
Visit Wizako.com

More questions from Speed Time, Races

  1. Speed Time - Races
  2. Speed Time - Geometry
  3. Speed Time - Cars
  4. Speed Time - Races
  5. Speed Change
  6. Speed Time - Meeting point
  7. Speed Time - Races
  8. Relative Speed
  9. Speed Time - Races
  10. Boats and Streams
  11. Relative Speed
"Life is a race ... if you don't run fast ... you will be like a broken undaa" - Veerusahasra Buddhi