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 certain distance is covered at a certain speed. If half of this distance is covered in double the time, the ratio of the two speed is :

• 1] 1 : 16
• 2] 4 : 1
• 3] 2 : 1
• 4] 1 : 4

A thief is noticed by a policeman from a distance of 200 m. The thief starts running and the policeman chases him. The thief and the policeman run at the rate of 10 km and 11 km per hour respectively. What is the distance between them after 6 minutes ?

• 1] 100 m
• 2] 150 m
• 3] 190 m
• 4] 200 m

A train 100 m long is running at the speed of 30 km/hr. The time (in second) in which it passes a man standing near the railway line is :

• 1] 10 seconds
• 2] 11 seconds
• 3] 12 seconds
• 4] 15 seconds

A man travels the distance of his journey \(\frac{3}{4}\) by bus, \(\frac{1}{6} \)by rickshaw, and remaining 2 km on foot. The total distance traveled by the man is :

• 1] 12 km
• 2] 18 km
• 3] 20 km
• 4] 24 km

A train 350 m long is running at the speed of 36 km/h. If it crosses a tunnel in 1 minute, the length of the tunnel in metres:

• 1] 200 meters
• 2] 250 meters
• 3] 300 meters
• 4] 150 meters

A 6 × 6 grid is cut from an 8 × 8 chessboard. In how many ways can we put two identical coins, one on the black square and one on a white square on the grid, such that they are not placed in the same row or in the same column?

• 1] 216 ways
• 2] 324 ways
• 3] 144 ways
• 4] 108 ways

A ship, 40 kilometers from the shore, springs a leak which admits \(3\frac{3}{4}\) tonnes of water in 12 minutes. 60 tonnes would suffice to sink her, but the ship's pumps can throw out 12 tonnes of water in one hour. Find the average rate of sailing, so that she may reach the shore just as she begging to sink?

• 1]

  \(1\frac{1}{2}\) km/hr

• 2]

  \(2\frac{1}{2}\) km/hr

• 3]

  \(3\frac{1}{2}\) km/hr

• 4]

  \(4\frac{1}{2}\) km/hr

The driver of an ambulance sees a school bus 40 m ahead of him after 20 seconds, the school bus is 60 meter behind. If the speed of the ambulance is 30 km/h, what is the speed of the school bus?

• 1] 10 kmph
• 2] 12 kmph
• 3] 15 kmph
• 4] 22 kmph

Two cyclists start from the same place in opposite directions. One goes towards north at 18 kmph and the other goes towards south at 20 kmph. What time will they take to be 47.5 km apart ?

• 1]

  \({ \text{1}}\frac{1}{4}{ \text{ hrs}}\)

• 2]

  \({ \text{2}}\frac{1}{4}{ \text{ hrs}}\)

• 3]

  2 hrs 23 min

• 4]

  \({ \text{2}}\frac{1}{2}{ \text{ hrs}}\)