Quiz Discussion

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

A and B start at the same time with speed of 40 km/hr. and 50 km/hr respectively. If in covering the journey A takes 15 min longer than B, the total distance of the journey is :

• 1] 40 km
• 2] 48 km
• 3] 50 km
• 4] 52 km

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

Walking at the rate of 4 km an hour, a man cover a certain distance in 3 hours 45 minutes. If he covers the same distance on cycle, cycling at the rate of 16.5 km/hour, the time taken by him is :

• 1] 55.45 minutes
• 2] 54.55 minutes
• 3] 55.44 minutes
• 4] 45.55 minutes

A truck covers a distance of 550 metres in 1 minute whereas a bus covers a distance of 33 kms in 45 minutes. The ratio of their speed is :

• 1] 4 : 3
• 2] 3 : 5
• 3] 3 : 4
• 4] 50 : 3

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

A train is 250 m long. If the train takes 50 second to cross a tree by the railway line, then the speed of the train on Km /hr is :

• 1] 9 km/hr
• 2] 5 km/hr
• 3] 18 km/hr
• 4] 10 km/hr

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 boy stated from his house on bicycle at 10 am at a speed of 12 km per hour. His elder brother started after 1 hr 15 min on scooter along the same path and caught him at 1.30 pm. The speed of the scooter will be (in km/hr) ?

• 1]

  4.5 km/hr

• 2]

  36 km/hr

• 3]

  \(18\frac{2}{3}\) km/hr

• 4]

  9 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