Correct Answer - Option 3 : 45
Given
Length of train = 150 m
Time taken to cross the pole = 12 sec
Formula used
Distance = speed × time
\(x \ m/sec = x \times {18 \over 5} km/hr\)
Calculation
Speed of train = distance/time
⇒ 150/12 = 25/2 m/sec
\(⇒ {25 \over 2} \ m/sec = {25 \over 2} \times {18 \over 5} km/hr\)
⇒ 45 km/hr
