A bus travels 120 km at 60 km/h and 180 km at 90 km/h. What is the average speed for the entire journey ?

Correct option is A

Given:
Distance 1 = 120 km, Speed 1 = 60 km/h
Distance 2 = 180 km, Speed 2 = 90 km/h
Formula Used:
Average Speed = $$\frac{Total\ Distance}{Total\ Time}$$​​
Time = $$\frac{Distance}{Speed}$$​​
Solution:
Calculate the total distance covered during the entire journey.
Total Distance = 120 + 180 = 300 km
Calculate the time taken for each segment of the journey.
Time 1 = $$\frac{120}{60}$$​ = 2 hours
Time 2 = $$\frac{180}{90}$$​ = 2 hours
Total Time = 2 + 2 = 4 hours
Average Speed = $$\frac{300}{4}$$​ = 75 km/h
Final Answer
So the correct answer is (a)