wo trains 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively. In how much time will they cross each other, if they are sunning the same direction?
A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m. while another trainY starts from Ghaziabad at 4 p.m. and reaches Meerut at 5.30 p.m. The two trains will cross each other at:
Suppose, the distance between Meerut and Ghaziabad is x km.
Time taken by X to cover x km = 1 hour.
Time taken by Y to cover x km =
3
2
hours.
Speed of X = x kmph, Speed of Y =
2x
3
kmph.
Let them meet y hours after 4 p.m. Then,
xy +
2xy
3
= x
y
1 +
2
3
= 1
y =
3
5
hours =
3
5
x 60
min = 36 min.
So, the two trains meet at 4.36 p.m.
Workspace
Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one
Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:
Distance covered in 120 second = 1000 + length of train(l)
Distance covered in 80 seconds = 600 + l
So, distance covered in 40 seconds = (1000 + l) – (600 + l)
= 400 m
Speed = 400/40 = 10 m/s
Distance covered in 80 second = 80 x 10 = 800 m
So, 600 + l = 800
Length of the train (l) = 200 m
Workspace
A train reaches from A to B in 5 hours travelling at a speed of 60 km/hr. If its speed is increased by 15 km/hr, then the time of journey is reduced by
Total distance = speed x time
=60 x 5 = 300 km
If speed increased then new speed= 60 + 15 = 75 km/hr
New time = Total distance/speed
= 300/75= 4 hour
Time reduced by 5 – 4 = 1 hour
Workspace
Two trains 180 m and 120 m long respectively pass each other in 54 seconds when they run in the same direction and in 18 seconds when run in opposite directions. Find the speed of two trains
Let the speed of 1st train is S1 and speed of 2nd train is S2
Time = total distance/ relative speed 1) In same direction
54 = (180 + 120) / (S1 – S2) * 5/18
(S1 – S2)54 = (300 * 18)/5
(S1 – S2) = 20 2) In opposite direction
9 = (180 + 120) / (S1 + S2) * 5/18
(S1 + S2)18 = (300 * 18)/5
(S1 + S2) = 60
from 1 and 2
S1 = 40 km/hr
S2 = 20 km/hr
Workspace
If the speed of the boat in still water is 5 km/hr and the speed of the current is 10 km/hr, then find the time taken by the boat to travel 125 km with the current.
Speed of motorboat in still water is 35 kmph. If the motorboat travels 100 km along the stream in 2 hour 30 min, then the time taken by it to cover the same distance against the stream is
The speed of the motorboat in still water is 35 km/hr.
let the speed of the strem = x km/hr
Downstream speed = Distance/time
= 100 / 2.5
= 40 km/hr
Speed of stream = 35 + x = 40
x = 5 km/hr
Upstream speed = 35 – 5 = 30 km/hr
Time taken in upstream = 100/30 = 3 hour 20 min
Workspace
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
