The driver of a car, which is travelling at a speed of 75 km/h, locates a bus 80 m ahead of him, travelling in the ame direction. After 15 seconds, he finds that the bus is 40 m behind the car. What is the speed of the bus (in km/h)?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 46.2 km/hr
Let the speed of the bus be 'a' km/hr.
Time × speed = distance
Distance travelled = 80 + 40 = 120m
Relative speed = (75 - a).
15 × (75 - a) × 5/18 = 80 + 40
375 - 5a = 144
a = 46.2 km/hr.