1
1
Two trains of length 100 m and 80 m respectively run on parallel lines of rails. When running in the same direction the trains pass each other in 18 s, but when they are running in opposite directions with the same speeds as earlier, they pass each other
Two trains of length 100 m and 80 m respectively run on parallel lines of rails. When running in the same direction the trains pass each other in 18 s, but when they are running in opposite directions with the same speeds as earlier, they pass each other in 9 s. Determine the speed of the faster train.
1). 5 m/s
2). 10 m/s
3). 15 m/s
4). 20 m/s
1). 5 m/s
2). 10 m/s
3). 15 m/s
4). 20 m/s
This Question has 1 answers.
Let the speeds of both trains be ‘x’ and ‘y’.
When running in same directions, their relative velocity = x – y
Total distance to cross each other = 100 + 80 = 180
speed = distance/time = x – y = 180/18 = 10 ? they take 18 s to cross here
⇒ x – y = 10 ------Equation (1)
When running in opposite direction, relative velocity = x + y
speed = distance/time = x + y = 180/9 = 20 ? they take 9 s to cross here
⇒ x + y = 20 ------Equation (2)
Adding (1) and (2) = 2x = 30 ⇒ x = 15 m/s
⇒ Equation (1) ⇒ 15 – y = 10 ⇒ y = 15 – 10 = 5 m/s
∴ x = 15 m/s and y = 5 m/s
∴ Speed of faster train = x = 15 m/sSimilar Questions
- Point A is 30 metres to the east of point B. Point C is 10 metres to the south of Point A. Point D is 15 metres to the west of Point C. Point E is exactly in the middle of the Points D and F. Points D, E and F lie in a straight line. The length of the lin
- There are three taps A, B and C in a tank. They can fill the tank in 25 hrs, 20 hrs and 10 hrs respectively. At first all of them are opened simultaneously. Then after 1 hrs, tap C is closed and tap A and B are kept running. After the 4th hour, tap B is a
- In an alloy, zinc and copper are in the ratio 1 : 2. In the second alloy, the same elements are in the ratio 2 : 3. If these two alloys be mixed to form a new alloy in which two elements are in the ratio 5:8, the ratio of these two alloys in the new allow
- Directions: In a family of eight members, there are two married couples and a widow. B, an engineer is married to a doctor. D, an architect is the wife of C. F, a student is the only child of D. H is the son of G and his sister E is the niece of the manag
- Directions: In a family of eight members, there are two married couples and a widow. B, an engineer is married to a doctor. D, an architect is the wife of C. F, a student is the only child of D. H is the son of G and his sister E is the niece of the manag