A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is:
Answer & explanation
Correct answer: option 3
Formulae for average speed:
Average speed = \(\frac{\text{Total distance travelled}}{ \text{Total time taken}}\)
Time taken for 1st 160 km - \(\frac{160 }{ 64}\) = 2.5 hours
Time taken for last 160 km - \(\frac{160 }{ 80}\) = 2 hours
Average speed = \(\frac{\text{160 + 160}}{ \text{2.5 + 2}}\)
Average speed = \(\frac{\text{320}}{ \text{4.5}}\)
Average speed = 71.11 km/hr