Quiz Discussion

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 person can row a boat d km upstream and the same distance downstream in 5 hours 15 minutes. Also, he can row the boat 2d km upstream in 7 hours. How long will it take to row the same distance 2d km downstream?

• 1]

  \(\frac{{3}}{{2}}\) hours

• 2]

  7 hours

• 3]

  \(\frac{{29}}{{4}}\) hours

• 4]

  \(\frac{{7}}{{2}}\) hours

Sabarmati express takes 18 seconds to pass completely through a station 162 m long and 15 seconds through another station 120 m long. The length of the train is :

• 1] 132 m
• 2] 100 m
• 3] 80 m
• 4] 90 m

Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour ?

• 1] 9 min
• 2] 10 min
• 3] 12 min
• 4] 20 min

An aeroplane flies twice as fast as a train which covers 60 miles in 80 minutes. What distance will the aeroplane cover in 20 minutes ?

• 1] 30 miles
• 2] 35 miles
• 3] 40 miles
• 4] 50 miles

A runs \(\frac{7}{4}\) times as fast as B. If A gives B a start of 300 m, how far must the winning post be if both A and B have to end the race at the same time?

• 1] 1400 m
• 2] 700 m
• 3] 350 m
• 4] 210 m

A car travels 50% faster than a bike. Both start at the same time from A to B. The car reaches 25 minutes earlier than the bike. If the distance from A to B is 100 km, find the speed of the bike.

• 1] 120 kmph
• 2] 100 kmph
• 3] 80 kmph
• 4] 75 kmph

A plan left 40 minutes late due to bad whether and order to reach its destination 1600 km away in time, it had increase its speed by 400 kmph from its usual speed. Find the usual speed of the plane?

• 1] 600 km/hour
• 2] 400 km/hour
• 3] 1000 km/hour
• 4] 800 km/hour

If two incorrect watches are set at 12:00 noon at correct time, when will both watches show the correct time for the first time given that the first watch gains 1 min in one hour and second watch looses 4 min in two hours.

• 1] 6 PM, 25 days later
• 2] 12 noon, 30 days later
• 3] 12 noon, 15 days later
• 4] 6 AM, 45 days later
• 5] None of these

A man completes a certain journey by a car. If he covered 30% of the distance at the speed of 20kmph. 60% of the distance at 40km/h and the remaining of the distance at 10 kmph, his average speed is:

• 1] 25 km/h
• 2] 28 km/h
• 3] 30 km/h
• 4] 33 km/h