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: Option 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})