Question 3

# A bus covers a distance of first 50 km in 40 minutes, next 50 km at a speed of 2 km per minute and the next 30 km at a speed of 1.0 km per minute. What is its average speed during the entire journey?

Solution

Average  Speed = Total  distance  covered $$\div$$ Total  time  taken

Total distance travelled = 50 + 50 + 30 = 130 km.

Total time taken = Time taken to travel first 50 km + Time taken to travel next 50 km + Time taken to travel next 30 km = $$40 + 50\div 2 + 30\div 1 = 95$$ minutes = $$\frac{95}{60}$$ hours.

$$\Rightarrow$$ Average Speed = $$130\div \frac{95}{60} = 82.1$$ kmph