Quiz Discussion

Running at \(\frac{5}{4}\) of his usual speed, an athlete improves his timing by 5 minutes. The time he usually takes to run the same distance is:

• 1] 30 min.
• 2] 28 min.
• 3] 25 min.
• 4] 23 min.

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

The average speed of a train in the onward journey is 25% more than that in the return journey. The train halts for one hour on reaching the destination. The total time taken for the complete to and fro journey is 17 hours, covering a distance of 800 km. The speed of the train in the onward journey is :

• 1] 45 km/hr
• 2] 47.5 km/hr
• 3] 52 km/hr
• 4] 56.25 km/hr

Three runners A, B and C run a race, with runner A finishing 12 metres ahead of runner B and 18 metres ahead of runner C, in another race of same type runner B finished 8 metres ahead of runner C. Each runner travels the entire distance at a constant speed. The length of the race is :

• 1] 36 metres
• 2] 48 metres
• 3] 60 metres
• 4] 72 metres

Two ports A and B are 300 km apart. Two ships leave A for B such that the second leaves 8 hours after the first. The ships arrive at B simultaneously. Find the time the slower ship spent on the trip if the speed of one of them is 10 km/h higher than that of the other.

• 1] 25 hours
• 2] 20 hours
• 3] 15 hours
• 4] 20 hours
• 5] 24 hours

A man goes to a place on bicycle at speed of 16 km/hr and comes back at lower speed. If the average speed is 6.4 km/hr in total, then the return speed (in km/hr) is :

• 1] 10 km/hr
• 2] 8 km/hr
• 3] 6 km/hr
• 4] 4 km/hr

The length of a train and that of a platform are equal. If with a speed of 90 km/hr the train crosses the platform in one minute, then the length of the train (in meters) is ?

• 1] 500 meters
• 2] 600 meters
• 3] 750 meters
• 4] 900 meters

A postman goes with a speed of 36 km/h what is the speed of postman in m/s?

• 1] 4.5 m/s
• 2] 6 m/s
• 3] 5 m/s
• 4] 10 m/s

Ravi walks to and fro to a shopping mall. He spends 30 minutes shopping. If he walks at a speed of 10 km an hour, he returns home at 19.00 hours. If he walks at 15 km an hour, her returns home at 18.30 hours. How far must he walk in order to return home at 18.15 hours ?

• 1] 17 km/hr
• 2] 17.5 km/hr
• 3] 18 km/hr
• 4] 19 km/hr
• 5] None of these

A girl while walking diametrically across a semicircular playground, takes 3 minutes less than if she had kept walking round the circular path from A to B. If she walks 60 metres a minute, what is diameter of the play ground?

• 1] 60 m
• 2] 48 m
• 3] 84 m
• 4] 315 m
• 5] None of these