A bus moving at a speed of 45 km/hr catches a truck 150 metres ahead going in the same direction in 30 seconds. The speed of the truck is

Solution (By Examveda Team)

Let the speed of truck is = $$x$$ km/h
Their relative speed in same direction = (45 - $$x$$) km/h (Here (45 - $$x$$) has been written because bus crosses the truck which is running 150 meters ahead of it. i.e. Truck speed will be lower than that of bus)
According to the question
$$\eqalign{ & {\text{Time}} = \frac{{{\text{Total distance}}}}{{{\text{Total speed}}}} \cr & \frac{{150}}{{\left( {45 - x} \right) \times \frac{5}{{18}}}} = 30 \cr & \frac{{150 \times 18}}{{\left( {45 - x} \right) \times 5}} = 30 \cr & x = 27{\text{ km/h}} \cr} $$
So, speed of the truck is 27 km/h