Answer:
150 km/h
Step-by-step explanation:
It is given that,
Speed of a bus is 100 km/h and it can carry a maximum of 6 persons.
If speed of bus decreases in fixed proportion with increase in number of person, then we need to find the speed when 3 person are traveling in bus.
6 person = 100 km/h
1 person = (100/6) km/h
Ans
3 person =

Net speed = 100 km/h + 50 km/h = 150 km/h
Hence, if the required speed is 150 km/h.