A bus covers the first 80km at a speed of 40km/h. It covers the next 100km at a speed of 50km/h. What is its average speed?
- A45km/h
- B42km/h
- C44km/h
- D46km/h
Solution & Step-by-step Explanation
The formula for average speed is:
Average Speed=
Total Time
Total Distance
Total Distance = 80km+100km=180km
Calculate time for each part of the journey:
Time
1
=
Speed
1
Distance
1
=
40
80
=2hours
Time
2
=
Speed
2
Distance
2
=
50
100
=2hours
Total Time = Time
1
+Time
2
=2+2=4hours
Now find average speed:
Average Speed=
4
180
=45km/h
Average Speed=
Total Time
Total Distance
Total Distance = 80km+100km=180km
Calculate time for each part of the journey:
Time
1
=
Speed
1
Distance
1
=
40
80
=2hours
Time
2
=
Speed
2
Distance
2
=
50
100
=2hours
Total Time = Time
1
+Time
2
=2+2=4hours
Now find average speed:
Average Speed=
4
180
=45km/h