Question

a velocity travels half the distance L with the speed ​

Answer 1

$\sf Avg.\: velocity = \dfrac{Total\: distance\: travelled}{Total\:time\:taken}$

$\\ \\ \sf\implies \dfrac{L}{ \dfrac{L}{ \dfrac{2}{V_1} + } \dfrac{L}{ \dfrac{2}{V_2} } } = \dfrac{L}{ \dfrac{L}{2V_1} + \dfrac{L}{2V_1} } = \dfrac{2V_1V_2}{V_1V_2}$