Quiz Discussion

A train running at a speed of 54 km/hr crosses a platform in 30 seconds. The platform is renovated and its length is doubled. Now, the same train running at same speed crosses the platform in 46 seconds. Find the length of the train.

• 1] 180 metres
• 2] 200 metres
• 3] 210 metres
• 4] 240 metres
• 5] 450 meters

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

Two boys A and B start at the same time to ride from Delhi to Meerut, 60 km away. A travels 4 km an hours slower than B, B reaches Meerut and at once turns back meeting A, 12 km from Meerut. A's rate was :

• 1] 4 km/hr
• 2] 8 km/hr
• 3] 12 km/hr
• 4] 16 km/hr

A and B start from the same point and in the same direction at 7 am to walk around a rectangular field 400 m × 300 m. A and B walk at the rate of 3 km/hr and 2.5 km/hr respectively. How many times shall they cross each other if they continue to walk till 12.30 pm ?

• 1] Not even once
• 2] Once
• 3] Twice
• 4] Thrice

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

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

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

The area of square park is 25 sq. Km. Time taken to complete a round of the field once, at a speed of 3 kmph is:

• 1] 4 hours 60 minutes
• 2] 4 hours 50 minutes
• 3] 6 hours 40 minutes
• 4] 5 hours 40 minutes

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 speed \(3\frac{1}{3}\) m/sec when expressed in km/hr becomes :

• 1] 8 km/hr
• 2] 9 km/hr
• 3] 10 km/hr
• 4] 12 km/hr

A car traveling with \(\frac{5}{7}\) of its actual speed covers 42 km in 1 hour 40 minute 48 seconds. Find the actual speed of the car.

• 1]

  \(17\frac{6}{7}\) km/hr

• 2]

  25 km/hr

• 3]

  30 km/hr

• 4]

  35 km/hr