(A) 26 Sec
(B) 38 Sec
(C) 48 Sec
(D) 72 Sec
Correct Option is: D
Speed of the train = 90 km/hr
Converting the speed into m/sec
90 km/hr = (90* 5/18)m/s
= 25m/s
length of the train = distance travelled
we know distance = speed * time= (25*24)m
= 600 m
Distance travelled = Train length + telegraph post length
= (600 +1200)m
= 1800 m
Time = distance / speed
= ( 1800/25) sec
= 72 seconds
Hence the required answer is 72 seconds