Quiz Discussion

Two cars are moving with speed v1, v2 towards a crossing along two roads, If their distance from the crossing be 40 metres and 50 metres at an instant of time then they do not collide if their speeds are such that :

• 1]

  v1 : v2 =16 : 25

• 2]

  v1 : v2 e 4 : 5

• 3]

  v1 : v2 e 5 : 4

• 4]

  v1 : v2 e 25 : 16

The speeds of three cars are the ratio 2 : 3 : 4. The ratio of the taken by these cars to travel the same distance is :

• 1] 2 : 3 : 4
• 2] 4 : 3 : 2
• 3] 4 : 3 : 6
• 4] 6 : 4 : 3

A car after traveling 18 km from a point A developed some problem in the engine and the speed became \(\frac{4}{5}\) th of its original speed. As a result, the car reached point B 45 minutes late. If the engine had developed the same problem after traveling 30 km from A, then it would have reached 36 minutes late. The original speed of the car (in km/h) is:

• 1] 25 kmph
• 2] 30 kmph
• 3] 20 kmph
• 4] 35 kmph
• 5] None of these

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

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

An old man driving bike at 80 km per hour. However being sugar patient, old man could not travel continuously. He takes small breaks each of 2 minutes for every 15 minute of his drive. How much distance the old man will cover in 90 minutes?

• 1] 112 Km
• 2] 104 Km
• 3] 89 Km
• 4] 118 Km

In a race of one kilometre. A gives B a start of 100 metres and still wins by 20 seconds. But if A gives B a start of 25 seconds, B wins by 50 metres. The time taken by A to run kilometre is :

• 1]

  17 sec

• 2]

  \(\frac{{500}}{{29}}{ \text{sec}}\)

• 3]

  \(\frac{{1200}}{{29}}{ \text{sec}}\)

• 4]

  \(\frac{{700}}{{29}}{ \text{sec}}\)

The ratio of speeds of A and B is 2 : 3 and therefore A takes 20 minutes more time than B. What is the ratio of time taken by A and B?

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

Each wheel of a car is making 5 revolutions per second. If the diameter of a wheel is 84 cm, then the speed of the car in cm/sec would be :

• 1] 420 cm/sec
• 2] 264 cm/sec
• 3] 1000 cm/sec
• 4] 1320 cm/sec

2 km 5 metres is equal to ?

• 1] 2.5 km
• 2] 2.005 km
• 3] 2.0005 km
• 4] 2.05 km