The wheel of loco engine,7.5 meters in radious,makes7 revolutions in 9 seconds. The speed of the train in km/hr would be;
(a) 130 (b)135 (c) 150 (d) 132
Given that: The radius of the wheel (r) = 7.5 m
Distance covered by wheel in 9 seconds = Circumference of wheel
Revolutions
= 
=
) m = 330 m
Distance covered in 1 second = 
m
So, required speed= 
km/hr = 132 km/hr.
Hence, the correct option is (d).