Question

If a car covers 2/5th otlf the total distance with vl speed and the 3/5th distance with v2 then average speed is ____

Answer 1

$$v_{av}=\frac{s}{t}\\v_{av}=\frac{s}{\frac{2s}{5v_1}+\frac{3s}{5v_2}}\\ \\v_{av}=\frac{5v_1v_2}{3v_1+2v_2}$$