John drives 250 km at 50 km/h and then he drives 350km at 70km/h. Find his average speed for the whole journey in km/h.
Answer & explanation
Correct answer: option 2
Distance = Speed × Time
Time taken by John to cover 250 km = \(\frac{250}{50}\) = 5 hours
Time taken by John to cover 350 km = \(\frac{350}{70}\) = 5 hours
Average speed = \(\frac{350 + 250}{5 + 5 }\)
= \(\frac{600}{10}\)
= 60 km/h