Quiz Discussion

A, B and C start together from the same place to walk round a circular path of length 12km. A walks at the rate of 4 km/h, B 3 km/h and C \(\frac{3}{2}\) km/h. They will meet together at the starting place at the end of:

• 1] 10 hours
• 2] 12 hours
• 3] 15 hours
• 4] 24 hours

A person wishes to reach his destination 90 km away 3 hours but for the first half of the journey his speed was 20 km/hr. His average speed for the rest of the journey should be :

• 1] 4 km/hr
• 2] 0.75 km/min
• 3] 1 km/min
• 4] None of these

The average speed of a bus is one-third of the speed of a train. The train covers 1125 km in 15 hours. How much distance will the bus cover in 36 minutes ?

• 1] 12 km
• 2] 18 km
• 3] 21 km
• 4] 75 km
• 5] None of these

Two trains 105 meters and 90 meters long, run at the speeds of 45 kmph and 72 kmph respectively, in opposite directions on parallel tracks. The time which they take to cross each other, is:

• 1] 8 seconds
• 2] 6 seconds
• 3] 7 seconds
• 4] 5 seconds

An aeroplane flies from place A to place B at the speed of 500 km/hr. On the return journey, its speed is 700 km/hr. The average speed of the aeroplane for the entire journey is ?

• 1]

  \(566\frac{2}{3}{ \text{ km/hr}}\)

• 2]

  \(583\frac{1}{3}{ \text{ km/hr}}\)

• 3]

  \(583\frac{2}{3}{ \text{ km/hr}}\)

• 4]

  \(600{ \text{ km/hr}}\)

In a flight of 6000 km, an aircraft was slowed down due to bad weather. The average speed for the trip was reduced by 400 kmph and the time of flight increased by 30 minutes. The original planned duration of the flight was :

• 1]

  \({2\frac{1}{2}}\) hours

• 2]

  \({3\frac{1}{3}} \)hours

• 3]

  \({4\frac{1}{3}}\) hours

• 4]

  \({5\frac{1}{3}}\) hours

A journey of 192 km between two cities take 2 hours less by a fast train than by a slow train. If the average speed of the slow train is 16 km/hr less than that of the fast train, the average speed of the fast train is :

• 1] 32 km/hr
• 2] 36 km/hr
• 3] 48 km/hr
• 4] 64 km/hr

Two planes move along a circle of circumference 1.2 km with constant speeds. When they move in different directions, they meet every 15 seconds and when they move in the same direction, one plane overtakes the other every 60 seconds. Find the speed of the slower plane.

• 1] 0.04 km/s
• 2] 0.03 km/s
• 3] 0.05 km/s
• 4] 0.02 km/s
• 5] None of these

Walking \(\frac{3}{4}\) of his normal speed, Rabi is 16 minutes late in reaching his office. The usual time is taken by him to cover the distance between his home and office:

• 1] 48 min.
• 2] 60 min.
• 3] 42 min.
• 4] 62 min.
• 5] 66 min.

A boy is running at a speed of p kmph to cover a distance of 1 km. But, due to the slippery ground, his speed is reduced by q kmph (p > q). If he takes r hours to cover the distance, then:

• 1]

  \(\frac{1}{r} = p - q\)

• 2]

  r = p - q

• 3]

  \(\frac{1}{r} = p + q\)

• 4]

  r = p + r