Aptitude :: Time and Distance

Practice :: Time and Distance - General Questions
Time and Distance - General Questions

Page Title 6. An airplane covers a certain distance in 5 hours at a speed of 240 kmph. To cover the same distance in 1(2/3) hour, at what speed should it travel:
600 kmph
750 kmph
720 kmph
850 kmph
Answer: option C

Distance = (240 x 5) = 1200 km

Speed = Distance/Time

Speed = 1200/(5/3) km/hr. [We can write 1(2/3) hours as 5/3 hours]

∵ Required speed = (1200 x 3/5) km/hr. = 720 km/hr.



7. In a flight of 600 km, an aircraft slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/h and flight time increased by 30 minutes. The flight duration is:
3 hour
5 hour
7 hour
1 hour
Answer: option D

Let the duration of the flight be X hours.

Then, 600/X - 600/X + (1/2) = 200

⟹ 600/x - 1200/2X + 1 = 200

⟹ X(2X + 1) = 3

⟹ (2X + 3)(X - 1) = 0

∵ X = 1 hr.



8. The ratio between the speed of two trains is 7 : 8. If the second train covers 400 km in 4 hours, then the speed of the first train is:
57 km/hr
87.5 km/hr
42 km/hr
80 km/hr
Answer: option B

Let the speed of two trains be 7X and 8X km/hr.

Then, 8X = 400/4 = 100

⟹ X = 100/8 = 12.5

∵ Speed of first train = (7 x 12.5) km/hr = 87.5 km/hr.



9. On a tour a man travels first 160 km at 64 km/h and next 160 km at 80 km/h. The average speed for the first 320 km of the tour is:
71.11 km/hr
75 km/hr
65 km/hr
60 km/hr
Answer: option A

Total time taken = (160/64 + 160/80) hrs. = 9/2 hrs.

∵ Average speed = (320 x 2/9)km/hr = 71.11 km/hr.



10. sachin is traveling on his motor cycle and has calculated to reach point A at 2 pm. If he travels at 10 kmph, he will reach there at 12 noon if he travels at 15 kmph. At what speed should he travel to reach A at 1 pm?
20 kmph
15 kmph
12 kmph
10 kmph
Answer: option C

Let the distance travelled by X km.

Then, X/10 - X/15 = 2

⟹ 3X - 2X = 60

⟹ X = 60 km

Time taken to travel 60 km at 10 km/hr = (60/10)hrs = 6 hrs.

So, Sachin started 6 hours before 2 P.M. i.e., at 8 A.M.

∵ Required speed = (60/5)hrs. = 12 km/hr.




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