Question

A vehicle runs on a straight road of length 'L' It travels half the distance with speed 'V' and the remaining distance with speed ($\frac{V}{3}$). Its average speed is

• A. $\frac{3V}{2}$
• B. V
• C. $\frac{V}{2}$
• D. $\frac{2V}{3}$

Answer 1

Answer: (C)

$\frac{V}{2}$

Answer 2

Solution:

Let total distance = L.
Distance for each half = L/2.

Time for first half = (L/2)/V = L/(2V).

Time for second half = (L/2)/(V/3) = (3L)/(2V).

Total time = L/(2V) + 3L/(2V) = 4L/(2V) = 2L/V.

Average speed, V_avg = Total distance / Total time = L / (2L/V) = V/2.