Train A takes 6 hours more than train B to cover a distance of 800 km. If the speed of train A is doubled, then it takes 2 hours less than train B. What is the speed of train B?
80 km/h
Let train B take t hours for 800 km; then train A takes (t + 6) hours.
Doubling the speed halves the time:
(t + 6)/2 = t - 2
t + 6 = 2t - 4
t = 10 hours
Speed of train B = 800 ÷ 10
= 80 km/h
Hence, 80 km/h.
Similar Questions
Two trains running in opposite directions cross a man standing on the platform in 25 seconds and 32 seconds respectively and they cross each other in 30 seconds. The ratio of their speed is:
A gun is fired at a distance of \(4.2\text{ km}\) from a tree. If the sound is heard after \(13\text{ s}\), then the speed of sound is:
A girl takes 30 seconds to cover a distance of 300 meters on a scooter. What will be her speed in km/hr?
A person takes 5 hours to cover a distance of 300 km by car. By how much (in km/hr) should he increase his speed so that he covers the same distance in 4 hours?
If a boy goes to school from his home at a speed of 8 km/hr, he is late by 30 minutes and if he goes at a speed of 12 km/hr, he reaches on time. The distance from his home to school is ______.
A man goes to his office at a speed of 10 km/hr and returns at a speed of 15 km/hr. If it takes a total of 6 hours, what is the distance between his house and office?
A car takes 4 hours to cover a distance of 300 km. What should be the speed of the car in km/hr to cover the same distance in 3/4 of the previous time?
In a certain time, a certain distance is covered. If 50% more distance is covered in 40% less time, then what will be the ratio of speed in both situations?
Rohit and Dinesh are 64 km apart. Rohit can walk at a speed of 15 km/hr and Dinesh at the speed of 17 km/hr. In how many hours will they meet if they are travelling towards each other?
Amit covers a distance in 10 hours at a speed of 40 km/h. If he wants to cover the same distance in 8 hours, what should his speed be?
Important Questions from Speed Time and Distance
A train travelling at a speed of 72 km/hr crosses a post in 20 seconds. If it crosses another train travelling at a speed of 54 km/hr in the same direction in 1 minute 45 seconds, then the difference in length between the two trains is
Rajiv's boat can travel along the current at the 8 km/hour and against the current at the rate 6 km/hour. Find the time taken by the boat to sail 28 km in still water.
Two trains running in opposite directions cross a man standing on the platform in 25 seconds and 32 seconds respectively and they cross each other in 30 seconds. The ratio of their speed is:
A worker covers a distance of 81 km in 11 hours. He travels partly on foot at 4.5 km/h and partly on bicycle at 15 km/h. What is the distance covered on the cycle?
A car travels from a place X to place Y at an average speed of v km/hr from y to X at an average speed of 2v km/hr, again from X to y at an average speed of 3v km/hr and again from y to x at an average speed of 4v km/hr. Then the average speed of the car for the entire journey
