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

A man goes to the fair with his son and dog. Unfortunately man misses his son which he realizes 20 minutes later. The son comes back towards his home at the speed of 20 m/min and man follows him at 40 m/min. The dog runs to son and comes back to the man to show him the direction of his son. He keeps moving to and fro at 60 m/min between son and father, till the man meets the son. What is the distance traveled by the dog in the direction of the son?

• 1] 800 m
• 2] 1675 m
• 3] 848 m
• 4] 1000 m
• 5] None of these

A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is:

• 1] 35.55 km/hr
• 2] 36 km/hr
• 3] 71.11 km/hr
• 4] 71 km/hr

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

A bus moving at a speed of 45 km/hr catches a truck 150 metres ahead going in the same direction in 30 seconds. The speed of the truck is :

• 1] 27 km/hr
• 2] 24 km/hr
• 3] 25 km/hr
• 4] 28 km/hr

A dog start chasing to a cat 2 hour later. It takes 2 hours to dog to catch the cat. If the speed of the dog is 30 km/h. what is the speed of cat?

• 1] 10 km/h
• 2] 12 km/h
• 3] 15 km/h
• 4] 20 km/h

An ant moved for several seconds and covered 3 mm in the first second and 4 mm more in each successive second than its predecessor. If the ant had covered 1 mm in the first second and 8 mm more in each successive second, then the difference between the path it would cover during the same time and actual path would be more than 6 mm but less than 30 mm. find the time for which the ant moved (in seconds).

• 1] 5 s
• 2] 4 s
• 3] 6 s
• 4] 2 s
• 5] None of these

A motor boat takes 2 hours to travel a distance of 9 km downstream and it takes 6 hours to travel the same distance against the current. The speed of the boat in still water and that of the current (in km/h) respectively are:

• 1] 6, 5 km/h
• 2] 3, 1.5 km/h
• 3] 8, 5 km/h
• 4] 9, 3 km/h

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

A monkey climbs a 60 m high pole. In first minute he climbs 6 m and slips down 3 m in the next minute. How much time is required by it to reach the top?

• 1] 35 minutes
• 2] 33 minutes
• 3] 37 minutes
• 4] 40 minutes