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

Anna left for city A from city B at 5.20 am. She travelled at the speed of 80 km/hr for 2 hours 15 minutes. After that the speed was reduced to 60 km/hr. If the distance between two cities is 350 kms, at what time did Anna reach reach city A ?

• 1] 9.20 am
• 2] 9.25 am
• 3] 9.35 am
• 4] 10.05 am
• 5] None of these

Two trains 150 m and 120 m long respectively moving from opposite direction cross each other in 10 sec. If the speed of the second train is 43.2 km/hr, then the speed of the first train is :

• 1] 54 km/hr
• 2] 50 km/hr
• 3] 52 km/hr
• 4] 51 km/hr

The speeds of John and Max are 30 km/hr and 40 km/hr. Initially Max is at a place L and Jhon is at a place M. The distance between L and M is 650 kms. John started his journey 3 hours earlier than Max to meet each other. If they meet each other at a place P somewhere between L and M, then the distance between P and M is :

• 1] 220 kms
• 2] 250 kms
• 3] 330 kms
• 4] 320 kms

If a person walks at 14 km/hr instead of 10 km/hr, he would have walked 20 km more. The actual distance travelled by him is:

• 1] 50 km
• 2] 56 km
• 3] 70 km
• 4] 80 km

A student goes to school at the rate of \(2\frac{1}{2}\) km/hr and reaches 6 min late. If he travels at the speed of 3 km/hr he is 10 min early. What is the distance to the school?

• 1]

  4 km

• 2]

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

• 3]

  1 km

• 4]

  \(3\frac{1}{2}\) km

Page and Plant are running on a track AB of length 10 metres. They start running simultaneously from the ends A and B respectively. The moment they reach either of the ends, they turn around and continue running. Page and Plant run with constant speeds of 2m/s and 5m/s respectively. How far from A (in metres) are they, when they meet for the 23rd time?

• 1]

  0 meters

• 2]

  10 meters

• 3]

  40 meters

• 4]

  \(\frac{{60}}{7}\) meters

• 5]

  None of these

A motorboat in still water travels at speed of 36 kmph. It goes 56 km upstream in 1 hour 45 minutes. The time taken by it to cover the same distance down the stream will be:

• 1] 2 Hours 25 Minutes
• 2] 3 Hours
• 3] 1 Hours 24 Minutes
• 4] 2 Hours 21 Minutes

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

Two boats A and B start towards each other from two places, 108 km apart. Speed of the boats A and B in still water are 12 km/h and 15 km/h respectively. If A proceeds down and B up the stream, they will meet after:

• 1] 4.5 hours
• 2] 4 hours
• 3] 5.4 hours
• 4] 6 hours