Question

2 trains of lengths 130m and 110m run on parallel tracks. When running in the same direction the faster train crosses the slower one in 20sec. When running in opposite direction at speeds same as their earlier speeds, they pass each other completely in 12 sec. Find the speed of the first train

Answer 1

total distance=110+130=240m
t1=20. (when running in the same direction)
S=D/t
S=240/20
s=12mps
(when the bodies are moving in the same direction their relative speed is the difference between their speeds.)
Va-Vb=12mps.....I

t2=12sec. (when they are moving in opposite directions)
s=d/t
s=240\12
s=20mps
(when two bodies are moving in opposite directions their relative speed is the sum of their speeds)
Va+Vb=20.....2
compareing 1&2
Va+Vb=20
Va-Vb=12
2Vb=8mps
Vb=4mps

by 1
Va-4mps=12mps
Va=16mps

Answer 2

Answer:

16m/s & 4m/s

Explanation:

the step by step procedure is given in the above photo.

the procedure is very simple and clear to point.