A man rides his bicycle for 10 kilometres at a speed of 12 kilometres per hour, then for another 12 kilometres at a speed of 10 kilometres per hour. What is his average speed for the entire trip approximately?
Answer & explanation
Correct answer: option 1
Total distance = 12 + 10 = 22 km
Time 1 taken = \(\frac{Distance }{Time}\)
= \(\frac{10}{12}\) = \(\frac{5}{6}\)
Time 2 = \(\frac{12}{10}\) = \(\frac{6}{5}\)
Total time = \(\frac{5}{6}\) + \(\frac{6}{5}\)
= \(\frac{25 + 36 }{30}\) = \(\frac{61}{30}\)
Average Speed = \(\frac{22 × 30}{61}\) = 10.819
= 10.8 km/h ( approx.)