(A) 2 Hours
(B) 3 Hours
(C) 4 Hours
(D) 5 Hours
Correct Option is: A
Let r = running time of the train
s= stoppage time of the train
D= total distance travelled by train
We have:
D/r= 120 and………..(1)
D/(r+s) =80………..(2)
Diviving (1)&(2),
D/r *(r+s)/D = 120/80
(r+s)/r =3/2
1 +s/r =3/2
s/ r = 3/2-1
s/ r = ½……………(3)
As, D=480 kms
480/r= 120
r=4
put r value in (3),we get
s/4 =1/2
S = 2 hours