Let the speed of the train be St and the speed of the CAT be Sc.
Case 1:
The CAT runs towards the train.
Case 2:
The CAT runs away from the train.
Equating (i) and (ii),
St : Sc = 4 : 1
Hence, option 1 is the correct one..
or
Let ‘c’ and ‘t’ be the velocity of train and cat.
Get the diagram right (if diagram is required)
1st case :
Train and cat meet at point A in the diagram.
Let train be at a distance of “y” from the entrance of the tunnel.
Cat is at a distance of 3x/8 from the entrance of the tunnel (Cat is between A&B. i.e. 3x/8 from A and 5x/8 from B )
So, by the time train runs a distance of y, cat runs a distance of 3x/8 (As they reach entrance at the same time)
Hence, equating the time taken, we have, y/t = 3x/8c
2nd case:
Train and cat meet at point B in the diagram.
Train travels a distance of y + x (Till the end of the tunnel)
Cat travels a distance of 5x/8 (Till the end of the tunnel)
Both reach at the same time, hence we can equate the time. We get, y + x/t = 5x/8c.
Subtracting the 2 equations, we have, (2nd case – 1st case) :
[(y +x)/t] – [y/t] = (5x/8c) – (3x/8c)
x/t = 2x/8c
c/t = 1/4.
t/c = 4/1.