Quiz Discussion

A star is 8.1 × 1013 km away from the earth. Suppose light travels at the speed of 3.0 × 105 km per second. How long will it take the light from the star to reach the earth ?

• 1] 7.5 × 103 hours
• 2] 7.5 × 104 hours
• 3] 2.7 × 1010 seconds
• 4] 2.7 × 1011 seconds

2 km 5 metres is equal to ?

• 1] 2.5 km
• 2] 2.005 km
• 3] 2.0005 km
• 4] 2.05 km

Rohan, Shikha's boyfriend, had to pick her from her home for a live concert on her 23rd birthday. The venue of the concert and Shikha's home were in opposite directions from Rohan's office. He got late because of some work at office and realised that if he goes to pick Shikha from her home, which was a 48-minute drive from his office, they would be late for the show by 16 minutes. He asked her to start from her home towards his office in an auto-rickshaw and himself started driving towards her home. Both of them started simultaneously, he picked her as soon as they met and they managed to reach the venue just in time for the concert. If Rohan drives at an average speed of 60 km/hr, find the speed (in km/hr) of the auto-rickshaw.

• 1] 16 km
• 2] 20 km
• 3] 12 km
• 4] 15 km
• 5] None of these

Buses start from a bus terminal with a speed of 20 km/hr at intervals of 10 minutes. What is the speed of a man coming from the opposite direction towards the bus terminal if he meets the buses at intervals of 8 minutes ?

• 1] 3 km/hr
• 2] 4 km/hr
• 3] 5 km/hr
• 4] 7 km/hr

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 person travels three equal distance at a speed of x km/hr, y km/hr and z km/hr respectively. What is the average speed for the whole journey ?

• 1]

  \(\frac{{xyz}}{{3\left( {xy + yz + zx} \right)}}\)    km/hr

• 2]

  \(\frac{{xyz}}{{\left( {xy + yz + zx} \right)}}\)    km/hr

• 3]

  \(\frac{{\left( {xy + yz + zx} \right)}}{{xyz}}\)    km/hr

• 4]

  \(\frac{{3xyz}}{{\left( {xy + yz + zx} \right)}}\)    km/hr

A train 300 m long is running with a speed of 54 km/hr. In what time it cross a telephone pole ?

• 1] 20 seconds
• 2] 15 seconds
• 3] 17 seconds
• 4] 18 seconds

A boy stated from his house on bicycle at 10 am at a speed of 12 km per hour. His elder brother started after 1 hr 15 min on scooter along the same path and caught him at 1.30 pm. The speed of the scooter will be (in km/hr) ?

• 1]

  4.5 km/hr

• 2]

  36 km/hr

• 3]

  \(18\frac{2}{3}\) km/hr

• 4]

  9 km/hr

P and Q are 27 km away. Two trains with speed of 24 km/hr and 18 km/hr respectively start simultaneously from P and Q and travel in the same direction. They meet at a point R beyond Q. Distance QR is :

• 1] 126 km
• 2] 81 km
• 3] 48 km
• 4] 36 km

In a flight of 6000 km, an aircraft was slowed down due to bad weather. The average speed for the trip was reduced by 400 kmph and the time of flight increased by 30 minutes. The original planned duration of the flight was :

• 1]

  \({2\frac{1}{2}}\) hours

• 2]

  \({3\frac{1}{3}} \)hours

• 3]

  \({4\frac{1}{3}}\) hours

• 4]

  \({5\frac{1}{3}}\) hours