Quiz Discussion

A gun is fired at a distance of 1.7 km from Ram and he hears the sound after 25 seconds. The speed of sound in meter per second is

• 1] 60 m/s
• 2] 62 m/s
• 3] 64 m/s
• 4] 68 m/s

The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 km in 4 hours, then the speed of the first train is:

• 1] 70 km/hr
• 2] 75 km/hr
• 3] 84 km/hr
• 4] 87.5 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

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

From two places, 60 km apart, A and B start towards each other at the same time and meet each other after 6 hours. If A traveled with \(\frac{2}{3}\) of his speed and B traveled with double of his speed, they would have met after 5 hours. The speed of A is:

• 1] 4 km/h
• 2] 6 km/h
• 3] 10 km/h
• 4] 12 km/h

Mr A started half an hour later than usual for the marketplace. But by increasing his speed to \(\frac{3}{2} \)times his usual speed he reached 10 minutes earlier than usual. What is his usual time for this journey?

• 1] 1 hours
• 2] 2 hours
• 3] 3 hours
• 4] 45 minutes
• 5] None of these

An aeroplane flies twice as fast as a train which covers 60 miles in 80 minutes. What distance will the aeroplane cover in 20 minutes ?

• 1] 30 miles
• 2] 35 miles
• 3] 40 miles
• 4] 50 miles

A plane left half an hour later than the scheduled time and in order to reach its destination 1500 kilometers away in time, it had to increase its speed by 33.33 percent over its usual speed. Find its increased speed.

• 1] 250 kmph
• 2] 500 kmph
• 3] 750 kmph
• 4] 1000 kmph
• 5] 1200 kmph

A runs \(\frac{7}{4}\) times as fast as B. If A gives B a start of 300 m, how far must the winning post be if both A and B have to end the race at the same time?

• 1] 1400 m
• 2] 700 m
• 3] 350 m
• 4] 210 m

The ratio of speeds of A and B is 2 : 3 and therefore A takes 20 minutes more time than B. What is the ratio of time taken by A and B?

• 1] 2 : 3
• 2] 2 : 5
• 3] 3 : 2
• 4] 3 : 5