A car travel at x km per hour for 1 hour and at y km per hour for 2 hours. Find its average speed
A. \(\frac{2x + 2y}{3}kmh^{-1}\) B. \(\frac{x + y}{3}kmh^{-1}\) C. \(\frac{x + 2y}{3}kmh^{-1}\) D. \(\frac{2x + y}{3}kmh^{-1}\)
Correct Answer: C
Explanation
Travelled x km/h for 1 hour \(\therefore\) traveled x km in the first hour. Traveled y km/h for 2 hours \(\therefore\) traveled 2y km in the next 2 hours. Average speed = \(\frac{x + 2y}{1 + 2}\) = \(\frac{x + 2y}{3} kmh^{-1}\)
