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 car covers a distance from town 1 to town 2 at the speed of 56 km/hr and from town 2 to town 1 at the speed of 53 km/hr. What is the average speed of the car ?

• 1] 53.5 km/hr
• 2] 54 km/hr
• 3] 55 km/hr
• 4] 55.5 km/hr
• 5] None of these

A motorboat in still water travels at speed of 36 kmph. It goes 56 km upstream in 1 hour 45 minutes. The time taken by it to cover the same distance down the stream will be:

• 1] 2 Hours 25 Minutes
• 2] 3 Hours
• 3] 1 Hours 24 Minutes
• 4] 2 Hours 21 Minutes

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

A is travelling at 72 km per hour on a highway while B is travelling at a speed of 25 mitres per second. What us the difference in their speeds in mitres per second ?

• 1]

  \(1\frac{1}{2} \)m/sec

• 2]

  2 m/sec

• 3]

  3 m/sec

• 4]

  5 m/sec

A train approaches a tunnel AB. Inside the tunnel is a cat located at a point that is \(\frac{3}{8}\) of the distance AB measured from entrance A. When the train whistles, that cat runs. If the cat moves to entrance A of the tunnel, the train catches the cat exactly at the entrance. If the cat moves to exit B, the train catches the cat at exactly the exit. The ratio of the speed of the train to that of the cat is of the order :

• 1] 3 :1
• 2] 4 : 1
• 3] 5 : 1
• 4] None of these

A moving train passes a platform 50 m long in 14 seconds and a lamp post in 10 seconds. The speed of the train (in km/hr) is :

• 1] 24 km/hr
• 2] 36 km/hr
• 3] 40 km/hr
• 4] 45 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 car traveling with \(\frac{5}{7}\) of its usual speed covers 42 km in 1 hr 40 min 48 sec. What is the usual speed of the car?

• 1]

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

• 2]

  35 km/hr

• 3]

  25 km/hr

• 4]

  30 km/hr

A bus covers three successive 3 km stretches at speed of 10 km/hr, 20 km/hr and 60 km/hr respectively. Its average speed over this distance is :

• 1] 30 km/hr
• 2] 25 km/hr
• 3] 18 km/hr
• 4] 10 km/hr