A man travels 75 km at speed 25 km/h and next 60 km at 20 km/h and there after travel 90 km at 15 km/h. His average speed is:
Answer & explanation
Correct answer: option 2
Average Speed = \(\frac{Total \;DIstance }{Total \;TIme }\)
Time 1 = \(\frac{DIstance}{Speed}\)
= \(\frac{75}{25}\)
= 3 hours
Time 2 = \(\frac{DIstance}{Speed}\)
= \(\frac{60}{20}\)
= 3 hours
Time 3 = \(\frac{DIstance}{Speed}\)
= \(\frac{90}{15}\)
= 6 hours
Total time = 3 + 3 + 6 = 12 hours
Total distance = 75 + 60 + 90 = 225 km
Average speed = \(\frac{225}{12}\)
= 18.75 km/h