Quiz Discussion

Each wheel of a car is making 5 revolutions per second. If the diameter of a wheel is 84 cm, then the speed of the car in cm/sec would be :

• 1] 420 cm/sec
• 2] 264 cm/sec
• 3] 1000 cm/sec
• 4] 1320 cm/sec

A passenger train 150 m long is travelling with a speed of 36 km/hr. If a man is cycling in the direction of train at 9 km/hr, the time taken by the train to pass the man is :

• 1] 10 seconds
• 2] 15 seconds
• 3] 18 seconds
• 4] 20 seconds

A man completes a certain journey by a car. If he covered 30% of the distance at the speed of 20kmph. 60% of the distance at 40km/h and the remaining of the distance at 10 kmph, his average speed is:

• 1] 25 km/h
• 2] 28 km/h
• 3] 30 km/h
• 4] 33 km/h

A boy rides his bicycle 10 km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km//hr. His average speed for the entire trip is approximately:

• 1] 10.4 km/hr
• 2] 10.8 km/hr
• 3] 11 km/hr
• 4] 12.2 km/hr

A soldier fired two bullets at an interval of 335 seconds moving at a uniform speed V1. A terrorist who was running ahead of the soldier in same direction, hears the two shots at an interval of 330 seconds. If the speed of sound is 1188 km/h, then who is the faster and how much?

• 1] Soldier, 22 km/h
• 2] Terrorist, 25 km/h
• 3] Soldier, 18 km/h
• 4] Terrorist, 20 km/h
• 5] None of these

An athlete claimed that his timing for a 100 m dash should be corrected because the starting signal was gives by a gun fired from a point 10 m away from him and the timekeeper was standing close to the gun. The error due to this could be (in seconds) :

• 1] 0.03 sec
• 2] 0.1 sec
• 3] 0.5 sec
• 4] 0.7 sec

A car traveling with \(\frac{5}{7}\) of its actual speed covers 42 km in 1 hour 40 minute 48 seconds. Find the actual speed of the car.

• 1]

  \(17\frac{6}{7}\) km/hr

• 2]

  25 km/hr

• 3]

  30 km/hr

• 4]

  35 km/hr

One third of a certain journey is covered at the rate of 25 km/hr, one forth at the rate of 30 km/hr and the rest at 50 km/hr. The average speed for the whole journey is :

• 1]

  35 km/hr

• 2]

  \(33\frac{1}{3}\) km/hr

• 3]

  30 km/hr

• 4]

  \(37\frac{1}{12}\) km/hr

A train covers a distance of 10 km in 12 minutes. If its speed is decreased by 5 km/hr, the time taken by it to cover the same distance will be :

• 1]

  10 minutes

• 2]

  13 minutes 20 seconds

• 3]

  13 minutes

• 4]

  11 minutes 20 seconds

A 75 metres long train is moving at 20 kmph. It will cross a man standing on the platform in :

• 1] 12 seconds
• 2] 14 seconds
• 3] 13.5 seconds
• 4] 15.5 seconds