Quiz Discussion

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

A person can row \(7\frac{1}{2}\) km an hour in still water. Finds that it takes twice the time to row upstream than the time to row downstream. The speed of the stream is:

• 1] 2 kmph
• 2] 2.5 kmph
• 3] 3 kmph
• 4] 4 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

A cyclist rides 24 km at 16 kmph and further 36 km at 15 kmph. Find his average speed for the journey ?

• 1] 15.38 km/hr
• 2] 15.5 km/hr
• 3] 16 km/hr
• 4] None of these

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

A thief seeing a policeman at a distance of 150 metres starts running at 10 kmph and the policeman gives immediate chase at 12 kmph. When the thief is overtaken the thief has traveled a distance of:

• 1] 750 m
• 2] 900 m
• 3] 800 m
• 4] 1 km

A boat covers 48 km upstream and 72 km downstream in 12 hours, while it covers 72 km upstream and 48 km downstream in 13 hours The speed of stream is :

• 1] 2 kmph
• 2] 2.2 kmph
• 3] 2.5 kmph
• 4] 4 kmph

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

Two rifles are fired from the same place at a difference of 11 minutes 45 seconds. But a man who is coming towards the place in a train hears the second sound after 11 minutes. Find the speed of train. (speed of sound = 330 m/s)

• 1] 72 kmph
• 2] 36 kmph
• 3] 81 kmph
• 4] 108 kmph
• 5] None of these

Train A travelling at 60 km/hr leaves Mumbai for Delhi at 6 pm. Train B travelling at 90 km/hr also leaves Mumbai for Delhi at 9 pm. Train C leaves Delhi for Mumbai at 9 pm. If all the three trains meet at the same time between Mumbai and Delhi, then what is the speed of train C if the distance between Delhi and Mumbai is 1260 km ?

• 1] 60 km/hr
• 2] 90 km/hr
• 3] 120 km/hr
• 4] 135 km/hr