Q 11-02-075JEE MainJEE Main 2023 (30 Jan, Shift 2)Easy
A vehicle travels $4\ \text{km}$ with speed of $3\ \text{km h}^{-1}$ and another $4\ \text{km}$ with speed of $5\ \text{km h}^{-1}$, then its average speed is
Answer: (D) $3.75\ \text{km h}^{-1}$
$$\bar v=\frac{8}{\frac43+\frac45}=\frac{8}{32/15}=3.75\ \text{km h}^{-1}$$
Solution by Sreeraj P, M.Sc Physics