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 \(\frac{2x + y}{3}kmh^{-1}\)
waec 1999mathematics

The correct answer is C. \(\frac{x + 2y}{3}kmh^{-1}\)

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 = \(\frac{x + 2y}{1 + 2}\)

= \(\frac{x + 2y}{3} kmh^{-1}\)

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