Quiz Discussion

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

Rani goes to school from her house in 30 minutes. Raja takes 45 minutes in covering the same distance. Find the ratio between time taken by Rani and Raja ?

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

In a race of 200 meters, B can gives a start of 10 meters to A, and C can gives a start of 20 meters to B. The starts that C can gives to A, in the same race is:

• 1] 30 meters
• 2] 25 meters
• 3] 29 meters
• 4] 27 meters

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

A train can travel 50% faster than a car. Both start from point A at the same time and reach point B 75 kms away from A at the same time. On the way, however, the train lost about 12.5 minutes while stopping at the stations. The speed of the car is :

• 1] 100 kmph
• 2] 110 kmph
• 3] 120 kmph
• 4] 130 kmph

A car goes 20 metres in a second. Find its speed in km/hr.

• 1] 20 km/hr
• 2] 18 km/hr
• 3] 72 km/hr
• 4] 36 km/hr

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.

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

Robert is travelling on his cycle and has calculated to reach point A at 2 P.M. if he travels at 10 kmph, he will reach there at 12 noon if he travels at 15 kmph. At what speed must he travel to reach A at 1 P.M.?

• 1] 8 kmph
• 2] 11 kmph
• 3] 12 kmph
• 4] 14 kmph

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