Question

A car travels 30 km at a uniform speed of 40 km/hr and the next 20km at a uniform speed of 20km/hr find its average speed.​

Answer 1

$\sf t1 = \frac{s1}{v1} = \frac{10}{20} = \frac{1}{2}$

$\sf t2 = \frac{20}{10}$

$\rm avg \: speed = \frac{total \: distance}{total \: time}$

$\begin{gathered}\sf avg \: speed = \frac{30}{ \frac{1}{2} + 2 } \\\sf avg \: speed = \frac{30}{ \frac{5}{2} } \\\sf avg \: speed = \frac{30 \times 2}{5} \\\sf avg \: speed = 12 \frac{m}{s} \end{gathered}$

• I hope this helps ( ╹▽╹ )